Others have covered the legalities. Just a few thoughts from flying with the odd recently ex-ATPL getting back into little aeroplane flying.
- Attitudes will be all different to what you've been used to in recent years.
- You CAN use more than 30 degrees of bank
- Some checks (airfield approach, en-route, pre-manoeuvering) checks need memorising again
- You may find that after years of IFR nav, you need to recalibrate to navigating visually again, and orienting in whatever your local area is. Extend that also to the good old PFL, which you may not have flown for some decades.
- Don't forget you don't have a co-pilot to give jobs to any more.
- Checklists out in flight, particularly in the circuit / approach / landing is a big no-no going back to flying single pilot.
- If you haven't already, spend £40 to get a UK ATPL issued on the back of your EASA ATPL. That will then automatically have IR(R) [the old IMCR] privileges embedded, at least for Annex II aeroplanes.
- Join the LAA, it's where all the fun stuff is going on (or BMAA if you have a taste for more fun, and less weight).
Enjoy, stay in touch here.
G