DONT GET ME WRONG. I love what I do, and wouldnt change it for any other lifestyle. But despite what people may think, it's not one permanent diving holiday - and sometimes it really gets to be like a very bad week at work!
When National Geographic TV International says it likes your pitch, and asks when you can deliver, its like Christmas and birthdays all rolled into one great feeling. It means a frenetic week of putting together a film shoot, consisting of 12 different flights to four separate locations in PNG and Thailand, collecting footage to edit and deliver by the agreed but very short deadline.
Ive travelled enough to know the tricks, even down to sending my underwater camera housings ahead by courier for me to collect. This works out far cheaper than paying excess baggage.
Everything is going just fine, and then, just five days before departure, comes the kick in the goolies. In response to a routine email about delivery materials, it turns out that NatGeo in Washington no longer accepts underwater footage in the format shot by my equipment.
As a freelance, I pay all my production expenses myself, and hope to make a profit from eventual sales of my films. Its not a great business model.
Not for me the luxury of having all my expenses paid, and using a broadcasters equipment. I have already forked out for air fares, accommodation and boat hire for the shoot, so with NatGeo wanting the programme I bite the bullet - an upgrade of equipment it has to be.
New cameras and housings - we need two, so thats just another £30,000 to spend. I have no choice.
Cameras Underwater doesnt have the housing in stock, but it has no problem with me contacting Gates direct in California. Theres still time to get a housing couriered to me.
And here it all starts to unravel. Gates has no stock until the next shipment from the factory, some two weeks after my departure date. Because of other commitments there is no way I can postpone the shoot - its then or never.
Emails to every Gates stockist in Europe and beyond all draw the same answer. Then Gates tells me there is one housing in stock - in Houston, Texas.
Our flight leaves Sunday. I can fly over Thursday, get back Saturday and still make the flight to Asia. Normally return flights to Houston would cost a few hundred quid, but thats as long as you stay at least 72 hours. Plus, Im booking late, its Easter and all flights are full.

EVENTUALLY I GET A FLIGHT for the bargain price of just under £2000, about four times what I would normally pay. Add this to the ever-unhealthier balance sheet.
Driving to the airport, I get the next kick where it hurts. It turns out that to meet specification I need a magic box called a NanoFlash - a snip at £2500 - and the guys in Houston dont stock it, as its another manufacturers add-on.
They might be able to get one couriered in, but cant be sure. So as my plane takes off from Heathrow, I know I could be on an expensive wild-goose chase, and wont find out till I land.
Houston comes up trumps - massive thanks to Joe at Marine Visions.
I get the new system home just in time to turn round back to Heathrow for the journey to PNG, which involves two overnight flights. By the time I land, Ive been in the air for almost a week.
Ive never known true jet lag till now. Im also another several hundred pounds poorer; the new housing pushed me way into excess-baggage charges.
And my first stop in Port Moresby is to call at the couriers and send my two unopened cases containing my now-obsolete underwater filming equipment back to the UK, for several hundred pounds more.
Plus, PNG customs insist that I must import them before re-exporting, hitting me for a further few hundred in duty.
But Im here. I go to bed at mid-day and wake at 5am after an almost-solid 18 hours sleep, feeling good and feeling excited. The mission is on target, and Im going to get some great diving and, I hope, some great images.
The first day, all goes like clockwork, with two extremely productive dives giving me exactly the footage I need.
The new HD camera is producing exceptional images and the Gates housing is a dream to use. But back in my room when I open the housing - disaster. The magic NanoFlash box stopped working after the first dive.
Initially, no panic, its probably something simple. But after working through the manual twice, I cant solve it. It looks like a helpline job but, of course, the help is in another time zone.

STILL JET-LAGGED, theres no way I can keep awake till the helpline starts work. The only option is to set my alarm for 4am, so I can talk to them before they stop work for the day.
After almost three hours of calls on my mobile at £2 a minute - you can do the maths, as its still too painful for me to think about - they conclude that I have a defective system, so will ship me a replacement, but there is no chance that it will reach here in time.
So the whole trip to PNG will have to be done again at my own expense - a cost of well over £10,000.
But Im here, no point in letting it get me down. One of my favourite wrecks is out there and Ive paid for a boat charter, so I may as well enjoy it.
The wreck is as good as I recalled, and going that bit deeper than I should have done gives me the slightly happy feeling of mild narcosis. Perhaps life isnt too bad after all...
Then as Im surfacing, theres acute pain in my left upper molar, a reverse block in some tiny air cavity in the tooth. I ascend inches at a time, then suddenly the pain clears, but theres something hard and crunchy in my mouth - my filling. My day is complete.
Back at the hotel, I get the name of a dentist who will see me today. Just as Im walking away from check-in, the manager calls me over: Arent you off to Thailand next Havent you heard about the state of emergency there
Civil unrest, troops in the streets, curfew - rather you than me!

Having emailed the first part of this article from location to DIVER, a little volcano in Iceland erupted, leaving John with a cancelled flight back to the UK and several days hanging around in Singapore before he finally got home, almost a week late. Then he tried again...


THE GOOD LUCK:
CONTACTING NEMO

THE PROCESS OF PITCHING a film idea seems as random as the mass spawning of fish, launching thousands of eggs into the plankton in the hope that one or two will survive. In the case of independent film-makers, we launch our ideas into the vast sea of the TV industry, usually in vain.
Whats worse is to receive blanket rejections, only to see your idea on screen a couple of years later. Did they just copy it, or did someone else coincidentally come up with exactly the same concept at the same time
My first piece of luck this time round had been the initial positive response from NatGeo TV International, which had successfully distributed my last film and is keen to work with me again.
The concept is simple - to look at the intriguing lives of clownfish and examine how the film Finding Nemo has affected stocks of these fish.
Twenty million clownfish worth $500 million will be taken from the wild this year. Its not so much a case of finding Nemo now as of saving him.
In Indonesia and the Philippines, fishermen use cyanide to stun the fish, with catastrophic results for the reefs. In Fiji, divers break off tonnes of live coral to decorate fish tanks. Throughout the Indian and Western Pacific oceans, these clowns of the reef are in serious danger through over-exploitation.
If I worked for the BBC, a team of researchers would work on the concept, scout locations and stories, and when the project structure was complete the production department would make bookings and arrange a shooting schedule for the camera crew.
My research department consists of me, my laptop and a string of contacts made over the years.
I know the best place for filming anemonefish, both in quantity and variety - Papua New Guinea. Emails to Dik Knight at Loloata and Max Benjamin at Walindi bring immediate and enthusiastic responses, plus Max sends me a recently published scientific paper concerning ground-breaking research into these fish in Kimbe Bay.
I realise that there is little chance of filming the collecting of fish in the wild, but I could mock it up using a couple of the local dive staff in the shots. So the plan is to get out there, collect as much footage as possible and make the film.
Dik meets us at the airport with interesting news. A US-based company in Port Moresby has been buying up wild caught fish from coastal villages and islands and shipping them to the States. For the PNG Dive Association this is bad news, as it has serious concerns about the effect on fragile stocks. For me its great news - if the exporter will talk to me.
The streak of luck is holding. Mark Schreffler at EcoEZ (Eco-easy) is more than helpful. We can visit its facility and he will arrange for us to accompany his collectors on a village visit.
I had expected a squalid warehouse on the outskirts of the city, but the high-quality modern facility is impressive.
I am also impressed by Marks sincerity and enthusiasm. If carried out responsibly and sustainably, he regards collection of fish for the aquarium trade as no different from any other form of fishing. He says it is bringing additional income to communities that were subsistence fishing, and teaching them that if they respect their reefs, they will provide a harvest for years to come.

WE GET TO VISIT Fishermans Island with the collectors, and Mark has also arranged for some of the islanders to go Nemo-catching for me. I have a sequence I never dreamt I would get.
The luck continues. The driver meeting our internal flight to drive us to Walindi asks if we would mind taking two people whose ride has not arrived.
And of all the people on the planet, we end up giving a lift to Geoff Jones and Phil Munday, the scientists from Australias James Cook University who wrote the paper Max had sent us! They are back to conduct further research.
By the time we arrive at Walindi, we have planned to interview the guys, film them at work and hear about their as-yet unpublished findings.
Back home in Cornwall, I had repeatedly come across the name Vorape Muthuwan in connection with farming Nemos, but never found contact details.
I had sent some optimistic email shots to try to track him down, and checking one evening I see the message: Hello. Im Vorapeth. Why do you want me

VORAPETH TURNS OUT to be Director of Marine Science at Thailands Burupha University, and the godfather of Nemo farming in Thailand.
He is also amazingly helpful, and passionate about his work. A hundred Nemos born in captivity is a hundred more Nemos on the reef is his motto.
The Irish god of luck has held my hand again.
Despite the state of emergency in Thailand, we arranged to fly there to meet. Vorapeth also promises us access to Nemo farms that are producing up to 10,000 fish per month for export.
An intense five days shooting an hour south of Bangkok at Chonburi follows. Sequences from the university laboratories, of fish laying eggs, and filming the farms, which includes me crawling on my knees in tanks containing hundreds of farmed Nemos awaiting shipment. Vorapeth and his team go out of their way to ensure that we get every shot we could need.
And, in a final stroke of luck, we visit Bangkoks illegal pet market and get shots of someone buying Nemos.
Three months later, Saving Nemo is delivered for distribution and the next batch of ideas is already out there - Panama, UK, back to SE Asia, Cuba, who knows which ideas may convert into film projects. I hope the luck of the Irish stays with me!

SAVING NEMO
MORE THAN 1000 TYPES of anemone are found worldwide, but only 10 host anemonefish, and all these are found in a range from the east coast of Africa to Hawaii.
Sea anemones are related to corals and to jellyfish, and like both they have harpoon-like stinging capsules that can kill fish that stray into them. But the anemonefish seem immune to their hosts venom, smearing mucous from the anemone over themselves.
So just as the anemone does not sting itself, it does not sting the fish. Its a sort of chemical camouflage - a fish in anemones clothing!
There are 28 species of anemonefish, and none is found in the wild without a host anemone. The fish can live for up to 20 years, and anemones are believed to live for more than 100 years.
Anemonefish have a fascinating social structure. The dominant and largest fish is usually the female, and the next largest her male mate.
If she dies, the male changes sex to become the breeding female of the group. The smaller fish on an anemone are non-breeding, waiting their turn to become the dominant pair, and if any is removed from the queue all the smaller fish will grow rapidly to move one step up the ladder.
The female lays hundreds of eggs on a rock in the shelter of the anemone, and constantly fans them with her fins.
Anemonefish are one of the few fish that tend their brood until they hatch into perfectly formed miniatures of their parent, and are released into the plankton.
Amazingly, those of the tiny fish that survive will return to the same reef to settle in a nearby anemone - though never the one occupied by their parents.

Dont miss the world premiere of John Boyles HD documentary Saving Nemo at Dive 2010. It is being
screened simultaneously at the World Underwater Film Festival in Marseilles.