Having spent some time over the weekend reading about the new part M maintenance and the likely increase in maintenance costs for C of A aircraft that are not in annex ll, I would expect the second hand cost of your British registered TB20 to drop again, and soon.
I would not agree that aircraft are bought with the hart and not the head. I have owned various aircraft, and shares in aircraft since 1991, and am currently many £1000’s up, which is not to say I have always got it right, but the current trend was predictable and much discussed on the BBS before it happened.
The new Euro LSA category will be in place within the next few years, which will again depress prices of older tec aircraft as brand new factory built aircraft with much lower running costs than our old Pipers and Cesspits flood in.
Rod1