Smoke alarm rules

Other

Hi,
I rent out a maisonette two bed property, ground floor is entrance door and steps up, then first floor, lounge and kitchen, then 2nd floor bedrooms and bathroom.
I need to fit new smoke detectors.
My understanding is: 1 x alarm per living quarters floor, so do I need 2 x alarms one on living room and kitchen floor and one on the bedroom floor?
Do they have to be wired into the mains or can they be battery powered? If mains do they have to be the new networked type?
Anything else I need to bear in mind please?
Thank you for your time.