Martin has set up an agreement with one of the airgun specialists over here for servicing (airmasters I think but dont quote me on that!), Michael Tawn is the distributor only.
However, I like to use Darrin of XTX who can turn his hand to anything as far as I know.
If you are confident getting inside a PCP then I believe they are straitforward, James McLachlan would be a good chap to ask, he was one of the first if not the first to get a TM in the UK. I believe he has done OK with his in a few comps