a few years back a mate had the RAC do an inspection of a cossie, the guy in fairness did research before going out and the guy selling grumbled as the guy spent about 3 hours checking the car out. It came with 12 months road side assistance thrown in,

The report came back pretty detailed but all in all ok, so we went and collected the car in the afternoon.

It broke down on the way home!! again in fairness it was idle control valve iirc so the car was revving like mad so maybe not something that would get picked up if it wasn't doing it when inspected.

He called the RAC to get recovered who said...

'you need to be with us for 24 hours before you can call us out and you only joined this morning!!'

to why my mate replied in a very shouty manner..

'well seeing as YOUR inspector just gave the ok on a car that has broken down before i got it home, I suggest you give me my £300 inspection charge back'

Their reply...

'we will be out within the hour sir'

Cant say I would use them personally, but may be hand if you are a long way away to check out if it is a wrong un or not.