I think all imports seem to have something interesting under the carpet in my old fto I found a cigarette under mine that had been dropped and burned through the carpet between the seats and just left there and some loose Japanese coins.
Back to the matter in hand I don't think taking £9-10k over a cars real value is right, It's maybe just me but that wouldn't sit right with me. No doubt the new owner will find there way onto this forum as we all do and realise they've been done, people on here look out for each other it's called club spirit.