Thanks for that - now that I think of it I'm not sure what a mortice lock is...
I've attached a photo of the lock on the back door with the key in it - I only noticed when the camera flashed that the lock has union written on it.
Also it might be worthwhile pointing out that the key...
Hi
I've just moved into a new place with a wooden back door and a mortise lock. I've just noticed that the door can be locked from the outside with no issue but when it is locked from the inside the key cannot be removed from the lock. I have tried wd40 to loosen it but it doesn't work...