The point is, you shouldn't HAVE a gap. They ought to have used a deeper piece of timber to cover the gap on the outside of the door, so there's still space on the inside to lift the door up enough to release the hinge. Leaving a gap is just lazy.
Yep, that's what I thought
Southies, your hubby ought to be able to add an extra piece of timber on the outside, fill it and paint it to match, and nobody would ever know. There's actually a height difference between the doorway of our toilet and the other rooms, but I never noticed until today. It's about 15mm, I'd say.