I can't see any more of the info I actually wanted making its way on here now (many thanks to the people who did help in that respect) so I will briefly address other points (made by people who I politely asked not to in the first place...):
NPTC certificates are not worth the paper they are written on. They are handed out like sweets by training institutions happy to have you back for another few courses. Competent people have the same piece of paper as incompetent people. I feel sorry for people who are good at tree work, have worked hard for and have the tickets but are lumped in with people who have the same tickets and are shìt at tree work. I equally dislike bad people being able to pass themselves off as good people.
People (who sell insurance or employ tree workers) who require tickets before quality are not the sort of people I want to deal with. Me not having tickets is a great way to make sure I never accidentally deal with these people.
I want to deal with people actively interested in quality rather than lazily relying on the aforementioned tickets (which are no reflection of quality).
Cost doesn't bother me. I'm currently part way through a course of training and qualification for a different type of work at a cost of £35,000 (though that cost could easily go to £50,000 or £60,000). It's a cost:benefit thing.
If I relied on tree work as my only source of income, I might toe the line and get some tickets for an easy life. This applies to gaining bargaining power with insurance firms or being able to work for people who demand NPTC certification. Luckily, I am fortunate enough to be able to pick and choose work that I do.
I hope that answers questions posed. I'm sure some will agree with me and I'm very sure some won't. Feel free to (a)debate intelligently or (b)do one.