I thought of the NPPL but went FAA PPC which gave me 5 hrs under the hood; a lot better than 1 hour's NPPL appreciation IIRC. The microlight is a so called hot ship with better panel (D180) than the C152 I trained in.
I would be definitely in favour of good maintenance of the 180 turn out of trouble, as the minimum insurance against bad things happening. Descending out of cloud expecting to meet air before ground seems one hope too many one bad day? Well maybe if I'm feeling lucky.
Either way, OP has a good plan to buy insurance, whether he gets it legit or not, but better legit in case he can add it to a higher licence later.