Hi sco vag
Cannot give any advice regarding the price but from my own experience on buying mint condition low milers from elderly people:
a. Fiat Punto for my son a few years back, mint condition, very low miles, the owners said it only went to the supermarket twice a week, four months of ownership and the gearbox went bang, casing cracked and large hole appeared, could see gearbox internals....new gearbox required.
b. 2008 VW Polo for daughter back in May 2011, mint condition, low miles, owner said he was only selling it because he had ordered a new Polo.
Test drive was ok, but after several days noticed juddering from clutch / gearbox on reverse along with a few other small problems.
Luckily local VW dealer under warranty found broken spring in clutch and replaced complete unit, dealer did not have to replace clutch but put it down to component failure....potential £1000 expense otherwise.
Bodywork looked mint on first inspection and at collection but after first wash noticed loads of scratches on every panel.....not impressed, further washes and it got worse, looked like the old fella had washed it with a brillo pad, local detailing centre (polishedbliss.co.uk) checked the car out and informed me the bodywork had had a mask type polish / wax applied just to get it sold. Several products later to try and repair the damage was a shambles as the damage was too deep.
Problems continued with gearbox / clutch so got shot of it in September 2011.
My only advice is check this motor out thoroughly before you part with hard earned cash, try and get a decent test drive and not just round the block.
Little old ladies will rip you off just as much as the local wide boy.
Good luck.