Hi Ladies and Gents

I had my clutch and slave replaced about 2 years ago and since have started to feel a slight bit of vibration through the pedal when changing gear. I'm hoping its not the dual mass flywheel as I'm not sure ill be able to replace that myself and will struggle to find a reputable service station that can do it, at a price I'm willing to pay.
The issue is I'm in to deep having put lots of mods and restoration into her, and really don't want to let this go until electric cars are very well established. Even when they are ill probably keep the cat then as a hobby.
Has anybody got any thoughts on

1. what the vibration could be?
2. recommend any reputable repair shops in the north west UK?
3. Changed the flywheel and made a thread on it?