Ahh yes I did these in the end shortly after posting.
So they don't press together and pull out, the tab needs sliding out slightly with a small screwdriver or tool, then pressing down, then pulling. Just pressing down and pulling will risk breaking them. And its also easy to flip the tab out so you can't press the locking tab down and lose them!
It isn't very intuitive, as most connectors I have seen either just squeeze and pull out, prize out or have a locking tab that is pulled up, this did none of that - slide tab out, squeeze, then prize out (but without losing the tab!).
Cheers.
