On 28/05/2020 17:11, JoeJoe wrote:
We have a solid oak door between the kitchen and the utility room.

The door was bought by us, brand new and with no holes for the handle
and latch mechanism.
It was fitted by our builders as part of an extension that we did
several years ago, and unfortunately it appears that the
handle/mechanism were not fitted/installed correctly - too far from the
edge of the door.

When the door is shut it is almost impossible to open it using the
handle, as the latch does not retract far enough (hardly any) into the
door when the handle is pushed down all the way. This has been the case
since it was fitted, so it is definitely not caused by a recent failure
of the mechanism.

Trying my best to explain, but happy to send photos/video if unclear.

Any idea how to resolve this please?
Take the handles off and check whether the square shaft is a good fit in
them - if loose then replace the shaft or pack the holes with something
rigid. See if the latch retracts enough if you turn the shaft with a
spanner or pliers - if not decide whether to replace the latch or
increase the rebate for the receiving plate (or whatever its called).