Mate - keep the rating valid! So that when you're thoroughly hacked-off with the arcane corners of Eurocracy in the ATPL exams, you can just go and hop into a Microlight and blow the cobwebs away.
Currently, we're trying to get agreement between all the various parties involved so that you'll be able to keep any or all microlight, SLMG or SEP NPPL ratings valid with the minimum of cost and fuss.