So. The heat had been leaking like a hot thing out of the gap behind
the oven door and we changed the rubber door seal which has helped
somewhat but has not cured the problem.

The door does not press as firmly against the oven as I would have
expected it to do. The oven is an Orbis which a)you almost certainly
have never heard of because b) it is a brand local to here and I am
not in the UK right now. But it has the usual bottom-mounted hinges
which flip over to release the door for removal.

Does this type of generic oven door have any sort of tension-adjust
mechanism anywhere? If so, what should I dismantle to get to it?

Any thoughts gratefully appreciated!

Thanks,

Nick