Thumb turn lock

If the property is a HMO property then you need to have a thumburn lock on the front door. Mortise deadlocks and sashlocks aren't allowed (Scotland).

There is no legal requirement to fit thumb turns in homes but for fire safety some letting agents could request it for their insurance purposes. You will need to get the right sized thumb lock which you measure from the outside door handle to the fixing screw on the side of the door (in line with the bottom of the euro lock) and then to the handle on the back of the door. Working outside in you then get the lock (40/50 for example the first number is front side). When you change the lock, first remove the fixing screw, if tight loosen the handles, then turn the key to ten to or ten past to align the cam and remove. Reverse the process to put back in. Make sure that the outside part of the euro lock does not stick out too far.

If there is already a Mortice lock with a cylinder fitted, you can buy a eurocylinder with a thumbturn on the inside and a key on the outside, and just change the cylinders over. Really simple to change, there is a screw bolt on the closing edge of the door in line with the lock and you simply unscrew it to pull the cylinder out, insert new cylinder, then screw the bolt back in.

Unsure of regs, but check with insurance company regardless as I know they don't always like it especially if it's a door with glass panes as they can be smashed and the door unlocked

As long as you get the correct size of lock it will be ok. If you don't size it properly your security can be reduced as they are easy to snap if wrongly measured on the external side of your lock. Take the measurement from the retaining screw on the centre of your door to end of your door handle where the cylinder shows.. This should never protrude any more than 2-3mm if correctly measured. I hope this is of some help to you.