Adrian wrote:

Hi All
The new studio was fitted with a nice new white UPVC door - standard
'front door' I guess.

The locking mechanism used to engage by closing the door and then
lifting the handle - which shot home three or four bolts on the side
of the door.

Recently there's been a procession of plumbers & etc in & out of this
door.
Now I find that the door mechanism seems to be broken !

The normal spring-loaded door catch seems to be stuck in the retracted
position, and you can't lift the door handle in order to operate the
locking bolts.

I am no expert on this, but I would bet that this is your problem. If
the door catch does not come out and latch into the jam, the rest of the
locking system will be unable to work. Look at the door catch and
determine that is central in both vertical and horizontal planes. If
not, pull down on the handle and try to move the latch so that it pops
out when you let go of the handle. They usually climb in the door, When
the handle is pushed down, so that a downwards push on the catch lets it
get back out again.

I have a similar problem on an internal door. When the grandchildren
come up, they pull the handle so far down that this nearly 30 year old
door's catch locks into the door and wont come out to latch it to
fasten. I had to file a chamfer on one corner of the catch.

Another problem with them and number one son is that they tend to pull
up our front door handle when it is open (this is exactly as your faulty
door should work to lock it with the key) and they can't pull the door
to because the latch is locked in an extended position.

A quick investigate allowed me to remove the lock
barrel - but this didn't seem to make any difference...

I doubt that the fault will be there.

Further investigation seems to involve dismantling the bolt mechanism
recessed in the opening side of the door. Any clues as to where the
problem may lie - or reassurances that I'm not going to end up
releasing a bag full of 'ping****its'...?

Before you get to this point, it will be to your advantage to call in
the original installer of the door. If it is the latch getting stuck
inside the door, then it is their problem and they should fix it for
free. Much less cost than trying to find all those ping****ets :-)

I am at the wrong end of a bad day, so I hope you understand all that I
have written

Dave