The default method of moving personnel around the world in WWII was by ship, usually in convoy. That would certainly have been the case here. Gibraltar was a major transit point for Mediterranean bound convoys to/from the UK, and those who got there via the Comet Line wouldn't have had long to wait for a voyage home. Of course, such a voyage was not without danger, but the routeing would have been out to the west, beyond the range of the shorter range Luftwaffe aircraft at least, but Condors, U-boats, surface raiders, etc all posed potential hazard. So did living in the UK of course. It was war, six long years of it...