UK Landlord Forum / Life

Hi, new forum member here.  I moved into a 3 roomed HMO with communal areas a couple of moths ago.  On the day I moved in I noticed that my door lock wasn't functioning as the housing for the latch wasn't attached to the frame so I was unable to lock the door.  Talking to the other 2 tenants they said theirs was the same.  I didn't want to cause a fuss for the first few weeks being a new tenant & also for the harmony of the shared house however, I noticed items missing from my room (pound coins mostly from my change jar).  I contacted the landlord and asked for the lock to be repaired, or if not repaired, replaced for my safety and security.
Landlord came a couple of days later and drilled a big keyhole through my door and screwed on a lock that was unsafe as it required a key to unlock it from both sides.  I informed the landlord that the lock did not comply with fire regulations and asked that it be removed and a more suitable lock be installed or the original lock be repaired by way of placing a latch holder on door frame.
Response came back as "I'll come and remove the unsafe lock but am not repairing/replacing the lock.
I do not know if a lock on a HMO room door has to have a lock by law however, would I be correct in assuming that since I am a tenant with an AST and I was unaware of the broken lock at commencement of my lease, could I then assume that the rent I pay includes my door with the lock that was there from day 1 of my lease 7 I should have the right to have it repaired so that it functions as intended ?
I invite discussion & any help on this topic.
Cheers