We haven't inspected the car, so we can't give you a definitive price - just a guide. Top money for one of these without the engine swap would be £4000-£5000. Whether or not it's worthy paying more for the engine swap, is something you'll have to decide for yourself. Has it been done well? Were the engine mounts replaced? Has the cooling system been upgraded? Was the clutch replaced at the same time (from memory the original bell housing won't fit), have the brakes been upgraded? How does it drive? Has the speedo been recalibrated? Check, check, and check again for rust. Mini are a hoot to drive and easy to get bits for, but keeping on top of the bodywork can be a full-time job.