Peter James wrote:Post #617 The end paragraph. Conditional  on EU membership.  At least 2 EU  nation states are members of the Commonwealth. Cyprus, Malta.The Irish Republic, a  EU nation state  has a bilateral agreement  on elections and free movement  with the UK  for almost a  hundred years. 
Gibraltar is a interesting case. 
David Davis is going to  be  very busy.
 
Indeed. But I wouldn't have thought that any agreement on voter eligibility that pre-existed the reciprocal arrangement with EU nation states (Maastricht 1992) would be affected: so the eligibility of nationals of Commonwealth states, the Irish Republic, Malta and Cyprus would continue. Gibraltar is a British Overseas Territory so, again, nationals would keep their eligibility (unless, of course, something happens to Gibraltar during the negotiations).