Not sure, but probably not is my best guess because I would expect that a UK glider pilot might need to demonstrate 'currency / recency' of gliding experience (not just power flying) to match the requirements of the proposed EU gliding licence. Those requirements are not likely to be regarded as onerous for those in current practice, but for lapsed glider pilots may require some up to date experience. Just my guess. All to be determined in due course through BGA / CAA negotiation etc.