I tried to unlock the sliding doors which have not been opened in a few months. There seems to be no way to unlock it with the key, ,it usually open no problem .the key turns a little but no click which usually means door is open. I want to avoid a lock smith any ideas on what can be the problem thanks, tried WD 40, tried putting pressure on door different ways to see if it might work, anyone know a lock smith in dublin 12 area which is fair on price