my licence is a CAA PPL (A) issued before the JAA was a twinkle in some eurocrates eye.
I´ve been in the same situation, letting my German ICAO-PPL expire about 5 years ago while flying 3-axis microlight. I recently took some refresher training and a skill test, and then got my ICAO-PPL back.
You should therefore also be able to get your ICAO-PPL back again fairly easily?