Many thanks for the info and the investigative work.
I’ve unwittingly misled the forum into thinking that the ‘negatives’ are part of the atlas. They’re completely separate – but are published by Sky.
They are not bound nor are they photocopies and are printed on ‘heavy’ card as a complete, but loose, set. They are a different scale to the maps. I’ve photographed them side by side.
I was aware of the differing desk and field editions. All my stuff is dated 1969 so not rare in any valuation sense, it’s just that I had not seen unbound maps (or negatives).
Are these unbound ‘card’ negatives a version of the field maps?