Padlocks would work but I'm sure a small bulldog clip or similar on each door would be adequate and easier. I'm sure I've read of some people doing that with the Barney when they've got a Syrian in there. Or just one of those little keyring clips would be fine.
Yes Mary sized cages especially with the low height do tend to be too small for most Syrians I think, can't seem to fit enough Syrian sized items in there
