Last year my house wasn't too wild so no issues with people potentially going into my room, apart from guests mistaking it for a bathroom which or using the ensuite I luckily got.
Anyway this year in my new house and new housemates I feel like there a higher chance of having more people round. The doors do not have locks but I was wondering if there was anything I could get for the outside of the door when I am not there to look it? obviously as its student housing can't rely too much on then allowing up to install something