The previous owners of the property have removed a couple of them and the remaining ones have either been damaged or damaged the frames due to the doors been wedged open. When I was sourcing new ones from the local builder’s merchants I was told you no longer have to install them to fire doors when you do a loft conversion so long as you install linked smoke alarms to all floors, which we have.
The main reason I would like not to have to replace them is the risk of kids or getting their fingers caught by the doors as they close. But if they have to stay they have to stay.