Most of the answers are in the referenced link.
Just a few points:
1. Once the EASA drafted Implementing Rules (the subject of the NPA public consultation expected from late May to late August 2008) are adopted by the EU Commission / Member States political process - approx early 2009 - any UK glider pilot flying a glider within the scope of EASA (i.e. non-Annex II glider) will need an EU licence, of which there will be two 'levels'. These are (a) Leisure Pilot's Licence (Sailplane) which will be sub-ICAO as regards the medical and (b) Sailplane Pilot's Licence - SPL - which will be ICAO compliant
2. The grandfathering of UK glider pilots to the EU licence(s) will be handled by the UK CAA - not EASA - and discussions have already started between the BGA and CAA on this, particularly because UK glider pilots do not currently have to have a (State-issued / endorsed) licence.
3. It is not a case of EASA not being able to cope with the work (see 2 above). You may have this impression because of the delay in the issue of the EASA Cs of A to UK glider owners who have applied since last October, but this delay has nothing whatsoever to do with EASA or the UK CAA, both of which have been very helpful, with the UK DfT, in getting the details of this airworthiness transition in place. The delay is with the EU Commission not having issued the relevant legal piece of paper to in effect authorise the DfT / CAA to issue the Cs of A of behalf of EASA. That is being worked on currently (and has been since last year) by the BGA et al.
4. The BGA is very active beind the scenes in planning ahead for all the likely issues that will or might arise in this whole transition to the EU environment of civil aviation regulation - none of which we invited but which is being imposed on us glider pilots / owners, thanks to the political agenda to europeanise everything that moves.
5. When the NPA on licences comes out I think you will find some good things in it for gliding, but also some 'issues' which we shall need to fight to have changed during the next phase of consultation etc, if we have not resolved them in the next two weeks in the final internal round of debate at EASA.
DGR / Gliding "expert" on EASA working groups