Implications of putting locks on bedroom doors - students

Tax Planning and Financial

Hi. I have students in a house on a joint assured shorthold tenancy agreement. Some of them have asked for a lock on their bedroom door and I am thinking of offering them this service on an optional basis for a cost of £50 for fitting the lock and supplying two keys. Are there any implications to doing this? I wondered if, having locks on their doors, they are in some way not part of a joint household and therefore the lease becomes invalid in some way, or that they have to have individual TV licences? Any comments