A couple of related queries:

Am I correct in thinking that the national-issue Wildings with phosphor bands were only issued initially in the areas around offices with an ALF machine, as with the phosphor commemoratives and the relevant regional Wildings?

At what point, if ever, did they go on general issue -- mid 1967 as with the commemoratives and the first Machins, or some earlier date?

Good evening MOZ,
Most of your queries can be answered by looking at the article produced by professor Austin J Barnes in an article by the name of " British post office phosphors ", that can be located by first going to the home page then go into 'downloads' where you will find philatelic studies, once entered you will be able to download the article, it's at the bottom of the list, I attempted earlier to include it with my posting but the size was over 2 meg, this being the limit for a normal inclusion.

I'm sure you will find it very informative, TTFN, WM.

Excellent! I didn't think about that file, and it has the details I was looking for.

In case anyone is interested in the answers, this is what it says:

The graphite and phosphor graphite stamps were issued only in the Southampton HPO area. Installation of production ALF machinery led to the expansion of the areas of issue of initially green and then blue phosphor stamps to S.E. London (late 1960), Liverpool (mid 1962), Glasgow (early 1963), W. London (summer 1965).

The first violet phosphor issues replaced the blue phosphor stamps in the areas with ALF machinery from August 1965. By early 1967 violet phosphor issues were replacing non phosphor stamps across the whole country.