I relently bought my crossfire from a dealer and he explained that there was no such thing as 'sold as seen' these days. Any trade seller is legally obliged to make sure a car is fit for purpose and provide a 3 month warranty minimum. You will need to confirm this but as far as i know this is an absolute law.
This is why they hate taking old cars as part exchange - he had to put my old Ford on ebay and loose money rather than put it on the forecourt for a higher asking price and risk a new owner making all sorts of claims.