Two or three years ago £750 with an MOT, £250 as it is, albeit a five pot but it's just a front wheel drive coupe, not an s2. Nice looking car but would need to be put back to factory on a few fronts to keep most on here happy also.
Now, with the 'new interest' folks paying too much, with the low mileage, maybe £750 as it is, maybe £1.5k if completely gone over and MOT'd, but you probably wouldn't get any more than that from anyone on here.
Low mileage is a fickle mistress, 15 years garaged is fine for bodywork but not good for the bits that move, doesn't stop rust (including inside the block) and doesn't stop all the rubbers perishing, although knowing this age group well I would not expect hardly any corrosion on the body, it's probably surface rust on the subframes etc.
Take it back to that MOT guy and sell it to him.
