So, no sale contract, no paperwork etc.!? Just a hand written receipt saying "received the sum of X for G-XXXX" sounds very informal for what could be exchange of a lot of dosh? The prebuy check you refer to, I assume would be the check done by your engineer?
Is there any particular paperwork you (or your engineer) would insist on seeing? Obviously tech log and nav / coms stuff but would you insist on seeing invoices for all work done?
I'm not quite at the stage of buying this minute IO, but will be looking for a Commander 114.
Are there are resident Commander "experts" on here, or that anyone can recommend?