Welcome to the forum flameport.

I've heard about this north/south gray/white cable divide before, but I wonder just when it supposedly started.

Does anyone know when white-sheathed cable was actually first on the market? I'm guessing not until the 1980s, or possibly late 1970s.

Pre-metric PVC cables were always gray sheaths as far as I know. I've certainly never seen any Imperial-sized cable in white, and metric cables I've seen (from living in Luton, Cornwall, Lincolnshire, and now Norfolk) which clearly date from the earlier 1970s all seem to be gray as well.

On a different tack, I like the old metal-clad Wylex Standard panels. Well made, a reasonably good internal layout, and far superior to a lot of the modern stuff in my opinion.