It depends on the situation & risk as to what you need, where you need it and to what type. so many combinations are possible and all could be appropriate in different situations - the BS don't always have the answer.
You could go on forever:
- Nothing to shop due to risk, size and layout, Pt 6 to flat (suitable separation present)
- Pt 1 to shop due to risk, size and layout, Pt 6 to flat (suitable separation present)
- Pt 1 to shop, extended to provide warning to flat, Pt 6 to flat for fire in flat (poor separation)
etc, etc....
And if you want to complicate it further lets add an internal common stairwell........
(I'd not want to have the flats detection element on the shop system except as a last resort as false alarms could cause a management issue - however of the risk & layout warrants the shop getting a warning from the flat as oppose to vice versa then it's a different set up again!)