So the front door (ancient timber one) is sticking a bit at the bottom,
directly below the latch. Perfectly possible to open it without problem
if you apply a bit of lift to the handle when you pull, but you know
what SWMBO and kids are like.

Something Must Be Done.

I am very loathe to take a plane to it, as I'm sure it's a weather thing
(has happened before) and the timber will shrink back again leaving too
large a gap. (Have had this experience before and consequently the
French windows spend all the winter with a large strip of duck tape down
the middle due to the massive gap between the doors).

How is it best to handle a problem like this?

David