Info on roof voids in purpose built flats

[William 29]

Does anyone have access to the info on compartmentation sizes/requirements in older blocks of flats that pre dates modern building regs?  As I understand it under current regs the 20m distance in any direction does not apply to domestic purpose group 1a flats?  If anyone has access to CP3 for the 40's 50's 60's or has an extract that would be most helpful    I have an issue with a large housing association that sees the loft areas in the common areas of flats as a potential risk and requires all loft areas inspecting.

Thanks all.