I've got one of these that sounds in comparable condition to yours, bought from City Air Weapons and Firearms a couple of years ago. I paid over £300 for it, which in hindsight was too much. I'd say £200-£250 would be more like it. They are very accurate, as you'd expect and the pellet seems to cover the 10m to the target very quickly, so it's powerful enough for it's intended purpose.
At 10m mine will knock over a Gammo steel rat target every time I hit the kill disc.
The South of England has 2 good things, the M1 and the A1. Both will take you to Yorkshire.