P-Torque are offering a Stage 1 remap for £295, I'm hoping to take mine there next month! They're in Wolverhampton so about an hour & a half's drive for you (bit less on the way back
)
They're also offering the remap plus a Milltek catback for £750, which is REALLY tempting...!
Closer to home though, Awesome GTI do Revo remaps and they're based in Irlam. I think it's around £500, but with it being Revo you could in theory switch it back with the right piece of kit (which you won't be able to do with P-Torque's remap unless you take the car back to them).
Both P-Torque and Awesome have their own sub-forum on here, probably best checking their threads out for up-to-date prices, contact details etc...