Ian,
BCO's in my area have accepted LD2 or LD2, plus all rooms adjoining escape routes, Grade D or E'ish, alarm system, in lieu of self closers, in houses of three floors. or two floors and loft, with a staircase enclosure.
They generally consult with fire service, and we agree.
The reasons being:-
1. Evidence from BCO's and FSO's that SC devices are removed after completion in dwellings, or the doors are wedged (I took the perko of the door to my own garage)
2. The assumption that probably occupiers will close doors to higher risk rooms at night
3. The additional detection will give earlier warning enabling folks to instigate their carefully prepared evacuation plan!!
Seems a better idea than folks dangling out of their loft conversion awaiting rescue by ladder, or waiting for the detectors in the staircase to go off.
Hey ho!
All the best,
Brian