Regaining your Class 1 is no big deal; you just get it with an AME as usual. I think that after a certain time - 5 years I think, but I'm not certain - you need to go back to Gatwick though, so don't leave it too long.
I drove my AME mad switching between a Class 1 and 2 for a few years; it was no problem really - except that he had to sort out what needed to be tested as different things last different lengths of time.