In message op.wayv5zokxafqef@desktop, MarkG writes
I need to adjust my front door, as it's not locking properly (can't
turn the key to lock it, because the hook arms are not engaging in the
frame correctly).

You don't say whether this is a PVCu panel door or a composite. It makes
a difference. It looks like a composite door from your photo.

I would call the bloke that fitted it a few months back, but he is a
useless ****, and I wouldn't trust him to tie his shoelaces properly.

I for the hinge caps off, and can see in/out and back/forth adjustment,
but not up/down.

The cam under the cap is for the in/out adjustment.

The screw is for left/right adjustment.

You should have a hole in the bottom of the hinge pillar for up/down. It
may have a plastic plug over the screw.

You should not have to adjust the hinges as they are usually set on the
bench in the factory but, the striker plate and the keeps may need
attention. If the frame and the door are square and there is an even gap
between the door and frame on all four sides you have a good starting
point.

Get a strip of ordinary copier paper about 2 inches wide and insert it
between the seal and the door. Close the door and try to pull the paper
out. It should grip the paper so that it can be pulled out without too
much trouble. On the hinge side use the cam under the cap to adjust the
tension.

Test the tension at the top. middle and bottom positions.

On the lock side, do the same and use the eccentric cams on the lock bar
to adjust the tension. Not all composite doors have cams on the lock
side and rely on the striker plate to control the seal tension.

Remove the top and bottom keeps and adjust the tension at the centre
point on the lock side.

Try the handle and if it now allows locking, it is one or both keeps
preventing locking. You can have hooks or bolts or both. If you only
have bolts the keeps will not prevent locking but if you have hooks and
they are prevented from going completely home by one or both keeps, that
is where your problem is.

You should not have to adjust the height or left/right at all.

The annoying thing is that some "I know better" fitters seem to think
that they need to adjust the setting after fitting. This can be true but
is usually a result of poor fitting.