Extraordinary! You can vote for a whole change in national government by post, but you can't vote in a parliamentary vote
Exactly! Not fit for purpose, by any modern standards.
MPs certainly have to be present in the UK Parliament to vote. I think that this is the case in most parliaments. I can imagine the reaction in the UK if MPs were allowed to vote without attending Parliament!
Would you still support postal votes if the MEP had indicated that he would have voted to support rules had he been present?