I wouldn't give up that easily just yet. Turn up in person and eye ball the owner and try and be as reasonable as possible. If that fails here are some things you might like to raise:-
- does he want the bad press from being named and shamed on pprune?
- how will he feel about you bringing a £50 old banger spray painted with "dont be rippped off by xyz" parked outside his club?
- ask him how he feels about a VAT audit followed by an income tax audit courtesy of HMRC
- mention that you are deeply concerned about the financial viability of his operation given that he is withholding your money and that you intend to write to your local mp, the chair of the aviation sub committee (or whatever it is called) and of course the CAA. Having contracted to the govt for a bit I can tell you there is nothing that gets a civil servant moving than having an MP chasing you. You will be surprised just how friendly some of these MPs are and how they love helping out. Afterall that is one of the things that you elect them for.
- ask him how disrupted his business would be if 50 ppruners all called up to book trial lessons over the next couple of months and then did a no show.
- also have a friendly word about the state of his aircraft and how you might have a mate of a mate who might write to the CAA concerning the safety and getting an audit undertaken of his maintenance records
- tell him you will go to your local paper and spill the dirt - they love these sorts of stories
- and if all else fails take em to small claims and get a written order (assuming you win). Then apply to the courts and get a charge put on his prize assets (presumably the aircraft) so that he will have to come grovelling to you in the future to get it released. By which time you might end up having to charge him some interest etc
Hopefully he will see reason with all of the above plus anything else you can think of and give you some of your hard earned back. Good luck.