I think the cars that are sticking around are in the main suffering from Low miles but also low service history.
I viewd so many with the old 'full history' only to find four visits in ten years.
My own GS is due for the market soon, but has 11 services, brand new AC compressor, cam covers done, wishbone done, new clutch 3 miles ago, 4 new tyres, 12 months MOT, and a fresh service despit only 370 since the last...oh and full LE spech...it will be at similar price to these dealer ones despite its higher miles...and I will not be dropping more than a pound or two.