Harry 11
Depends if the flats conform to current Building Regulations, if not common parts to be covered by Grade A LD2, and flats by a GRADE D LD2, but if the flats are modern and conform to the required compartmentation of Building Regulations doors, walls, & ceilings, a common alarm would not be required as the standard of fire safety with regards to the design & construction is at a safer level than an older building. In this case only a GRADE D LD2 for the flats would normally be recommended. The notice already served on the building would indicate that it is an older building that would require the necessary higher standard of fire safety in relation to fire detection and probably compartmentation that should be provided. To argue what legislation covers the building would not help your friend, costings could be very similar, safety of the occupants is the ultimate aim.