Not sure about the exact EASA aspect of it but recently or club PA28 went through ARC and we had to replace the engine driven pump and the unused electric back up. The engine one I can understand as the hours are recorded but the backup due to time. We suggested that the backup could either be made inop or even removed, but the CAA (don't ask why they were involved) insisted that it had to be removed or replaced, here's the kicker, it's cheaper to renew than remove although the lead time for a replacement is very loooooong.
Though it is never used shirley it would make more sense to mark it inop and in the worst case scenario it could serve as a backup, of course that being logical has no place within EASA thinking.
So much for safety.