If EASA doesn't encompass safety, what's the S for? Also, have a look at this link
ECAST
I think the level playing field objective comes from the old EEC where the removal of barriers to free trade within Europe was a main column in the the Treaty of Rome.
For the regulation of aviation EASA have already signaled that rules should be proportionate to the operation being regulated. They also have adopted AMC's to permit states to come up with ways of meeting Implementing Rules.
Lowest Common Denominator (LCD) will be the eventual result.
But wait, the IMCR is a national scheme just like the NPPL, the CAA will continue as an NAA doing EASA's work in the UK. Some aspects of UK aviation will fall outside the scope of EASA rulemaking and hence the CAA will have to devise ways regulating these 'left overs'.
Why not propose to the Captain of the Belgrano that we do things the French way? Sign up to the EASA IR but carry on as before with our UK IMCR. It could just work - couldn't it?
Sir George Cayley