I wouldn't be surprised if it doesn't line up. 80s guidance probably assumed mass nuclear war, while this document focuses on nukes that might be used by terrorists or "rogue states" aka North Korea or in the future Iran. In the former case there'd be massive nukes going off everywhere so dispersion would be emphasized, but in the latter case it's more likely to only have one nuke so rapid concentration and organization is more important

Difficult to say, the report has 250 pages covering a spectrum of responses and I personally have zero knowledge of what you yourself recollect from whatever guidance you were exposed to in the 1980s.

Are you thinking 1980s general public guidance, armed forces guidance, or scientific advice from comittee?

Would this be 1980s UK, US, or AU guidance?

"This 2021 Planning Guidance update addresses an expanded range of threat scenarios, including nation-state threats2 with much larger explosive yields. This guidance also considers nuclear devices delivered by ballistic missile or aircraft that can deliver detonations elevated above the surface. Low-altitude air bursts can increase the scale of the blast and thermal damage inflicted but may also significantly reduce local fallout impacts..."