Medically related NPPL statistics are I understand better than Class 2 ones
I'd be interested to see where that comes from. I can see the argument that a class-2 medical may not increase safety enough to be proportionate, but I don't immediately see how there can be a causal link between having more medical scrutiny and having more accidents.
I think it was David Roberts who produced some statistics over on the Flyer forum a while ago. I have had a quick search but cannot find the relevant thread at the moment.