TF, I don’t know if anybody knows for certain for your circumstances, but your best plan might be to get current again soon, so that your BGA licence can be converted to an EASA licence by what would then be “grandfather rights” without further tests and examinations, before April 2015. Don’t leave it to the last minute.
The reference to Annex 2 is to certain old glider types (listed in Annex 2 of the relevant legislation) which will be able to be flown after 2015 without an EASA licence. It would be rather restrictive. I don’t see how you could get to fly one after 2015 if you had not already become current again – your retraining would be on current (Annex 1) gliders, and to resolo I would expect you would have to do that on the gliding club’s training glider, which would be Annex 1.
But somebody else may know better.
HTH.
Chris N