Do all post-war prefabs contain asbestos?
Not all, but asbestos cement and board were standard prefab materials, so any unrefurbished example should be presumed to contain them until surveyed.
Is a BISF house dangerous to live in?
No — intact cement panels and linings in good condition are low risk. The risk moments are retrofit, recladding and roof renewal, which is why surveys come before those programmes.
Can insulation be fitted to a prefab with asbestos?
Yes — after a refurbishment survey identifies what the works will disturb. Affected materials are removed or encapsulated first, then the retrofit proceeds normally.