Can't check at the moment, but the door still fits OK into the frame.
The adjustment must have been small, but enough to make the door
catches (the 'hooks') not quite fit into the metal rectangular 'holes'
in the frame any more. I'm going to try slackening the hinge screws a
bit tonight to seee if I can fix the problem. I'm now assuming those
screws in the hinges are meant to be loose as adjusters, and weren't
meant to be tightened up as I thought before.

Cheers

Flummoxed