We have an external UPVC door which has been difficult to lock (raising handle) over the last few weeks and today my wife just couldn't lock it.
Done what I should have done some time ago and had a good look at the problem and it appears to me that the door has dropped slightly at the opening edge (I was able to lock it by heaving hard to raise the door) probably accentuated by the hot weather.
Thought it would be fairly easy to adjust by the hinges but having taken the covers off I find that there is what appears to be a knurled thread adjuster BUT its impossible to turn the knurled knob. There is, however, what appears to be a space specifically left in the construction of the lock to allow a tool to be inserted into the end of the threaded rod - possibly an Allen Key -but on close examination there doesn't appear to be any keyway or anything else for the key to lock into.
Can someone, please, advise me on how to progress this job.