Lots of great replies and I thought we were doing well, as both cats had jumped the gate. Then I woke up to find one had peed on the couch. So not impressed. So for now the gate is open and as DH is away at the moment, when he gets back I think I'll get him to remove a bar so they can go through the closed gate.
For those who've done this, did your little ones get their head stuck - that's my fear...