I really don't see what the problem is. Motor gliders are currently managed by the CAA. The majority of new gliders produced in Germany are equipped with engines so will come directly under the CAA rather than the BGA anyway. The BGA will continue as a representative body like the PFA, AOPA, etc.
The only things that will change would be licencing (why resist a move towards NPPL, surely it's beneficial and allows easier transition to other airsports and access to SEP) and probably costs (but flying has never been cheap).
I don't believe EASA will be the death knell for UK gliding. It will change, that's all. By the way, I'm a glider pilot as well as a PPL.
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