Anyway...In one case, althought it's clear that the door is too close a fit overall, so could use a few mm taking off one side, it also shows that the frame has a small bulge in it, of maybe 2 - 3 mm over 150mm, around the level of the lock. Clearly, if this was flat, it would reduce the amount I have to take off the door and leave me with a better fit all round.
It's not the most accessible spot, as these door frames don't have loose stops. I've been mulling a few approaches including: A lot of sanding (quite tricky all the way into the angle of the stop), planing (also hard to get right into the angle) or routing (potentially a good outcome but a bit or a pain setting up a jig for the job).
So what quick and easy approach am I overlooking, chaps?