I am in a similar position - Silver 'C', BGA Glider Pilot Licence but haven't flown gliders for 4-5 years.
Though no-one has given me a definitive answer the current best "guess" is that, when the new rules come into force, there will be a transition period - during which anyone who meets the requirements (including currency) will be able to get the EASA licence as a paperwork (plus payment) exercise.
If you wait until after the transition period then it's likely there will be training requirements / exams / ... needed.
I'm going to pay for a week course, to get current again in a club glider, and then apply for the EASA licence - seems the safest course of action to me.
OC619