Hi. I have moved to a flat that has an unusual lock. This is not the normal Yale lock that most people have on their front door. To lock the door you have to pull the handle upwards and turn the key. Also the key has to be used up side down. I think this is called a cylinder key or barrel key.
For security reasons I want to change this. I have looked on line and there are lots of criteria.
Size: 35/35 -35/40 to 50/55. What are these figures? are there different types like 3,4,5 or 6 barrels.
Need help here as I could do with buying on line.