Re sprinklers in stores:
They were either installed under local acts to allow larger compartment sizes or installed at the behest of the insurers or the occupant for property protection.
Henderson's was before my time but I have recollection that although there may have been sprinklers they were not covering the whole of the building.
Following the Manchester Woolworth's fire, the Fire Research Station was commissioned by the Home Office to look at the effect of sprinklers on this fire. As a result of the measurements taken during that work, further work was commissioned to look at the wider use of sprinklers for life safety, particularly the use of fast-response sprinklers. This concluded in 1992 by the publication of a summary report: Research Report 51, 'Sprinklers for life safety in Department Stores' by Harwood and Hume. In 1993 the 'Fire Safety and Safety of Sport Act 1987 (Commencement No.7) Order 1993' deleted reference in the 1971 FP Act to the provision of fire-fighting equipment for use by the occupants, and thus allowed fixed equipment, such as sprinklers, to be used as well.
Re Summerland: I cannot find the item refered to on the University of Birmingham website, only the references - the Google search just keeps taking me back to these. Anyone able to give me more details or a specific link, please?