It's heartening to see the value for this car, but I would demand to see the car up on a ramp before handing over £3500. It would have to be completely rot-free for that money. One would hope the dealer has that facility.
From the pictures it seems to have front and rear mudflaps which is good news as the fronts protect the sills from stonechipping and consequent rust. It may well have not done much mileage between MoTs but if it's been sat outside it will rust as fast as a £500 car, in the usual areas: rear floor, rear suspension mounts, inner rear arches etc.
Minor point too, it says 2002 car but that will be a 2001MY car on a 2002 registration. AFAIK production ended in 2001 so even if it were registered in July 2002, it would have sat on a dealer's lot, outdoors and unregistered for at least 6 months.