As a reference point I bought a T-reg 1.6 on 76,000 for £1300. You won't get a lot for it, even in perfect condition.
I'd keep it, especially if it's in perfect condition. It sounds like you're quite happy with it really anyway? Chances are at that mileage it won't just be the engine you'll need to replace to make people happy.. I'm guessing the clutch and the gearbox will be feeling a bit slack now, too?
I was going to sell mine at 80k, but I'm not sure it's worth it, unless I can do a straight swap for a lower mileage equivalent.