Our upvc front door had stopped working and the locks would not engage so my husband today stripped it and replaced the gearbox (with help from a lock shop in town). Its working well now, but you can open the door from outside without a key (unless its locked) and from inside you need to use the key to open it. This used to be the other way around. Is there something in the gearbox which can be switced to make this the correct way round again. The latch is facing the correct way.