Not sure if the UK has the same laws but here you can call the cops for disturbing peace and they'll do whatever they need to to make i stop. They even tow cars thats have been beeping for a while. Maybe you could try that first?

Where I live, especially in apartments, that is considered not only a noise disturbance, but a safety hazard as well. The manager would get in big trouble for not fixing it immediately. Since the alarm is constantly going off and ignored because it's broken, if it were to ever goes off for a legitimate reason, people would ignore it then too, which creates a potential safety hazard. I'd call the police and report a noise complaint, make sure to tell them that you tried multiple times to contact your manager and they still didn't do anything, and that this has been happening for almost over a week. Maybe even ask them to talk to your building manager, sometimes being scolded by the cops can scare them into doing their job better. It happened with my apartment complex, the building fire alarm constantly went off for no reason. So after a few times, both the cops and fire department said they need to actually fix and change the system or they would be charged/fined for failing to meet safety standards, it hasn't went off since.

Fire alarm like: "turn down for what?"

If you have a ladder or anything to stand on, it's really easy to replace the battery.

Set the building on fire?

call the fire department saying you hear a fire alarm going off in the vacant apartment