Personally I think you could probably find better - AVM tend to go more for fleet maintenance rather than individual aircraft. I've had a number of unpleasant experiences in their aircraft, but in all fairness the worst can't be blamed on them. If I do insist on flying diesels things will happen... They're also having possible CAA issues at the moment related to an engineer signing off an aircraft he wasn't qualified to work on. I don't know if Keith Smith still works out of Old Sarum but he was one of the few AVM engineers I really trusted, worth a try perhaps?