I know a good place in Sheffield but that's not really local for you. I've had 4 cars done there with very good results. Two Lexus and two Saab, tyres off, shot blasted, powder coated.
Re-reading your recent posts if the pressure is genuinely low it seems more likely you have a slow puncture rather than a badly fitting tyre. If you had the work done in August it would have shown up before now I think.