David,
There is talk of an EASA aerobatics rating coming in within the next 2 yrs. I don't know all the details but it will require something like the 10hr AOPA course and the latest update is that you will need 40 hrs straight and level after gaining your licence before you can get the rating.
This is if you wish to get an EASA licence endorsement in order to fly aerobatics in an EASA aerobatic aircraft. This will apply to Extras, CAPs and the certified Pitts (S2A, S1Ts and S2Cs) ie most of the training and rental aerobatics types.
However if you have a UK non expiring PPL and/or an NPPL and you are flying a non EASA aircraft ie an LAA/homebuilt type. Then you will not need any rating. Quite a lot of Pitts, lasers, Eagles etc fall into this category
There is talk of grandfather rights but you will need evidence of having done aerobatics. This can be the AOPA course or an Aerobatic competition or similar.
I do think this is unlikely to create any additional safety and will just discourage some people from taking up aerobatics. Indeed it might encourage private experimentation with aerobatics which can't be good.
The present system of self regulation has worked very well for many years. All EASA will do is increase costs and reduce safety.