The march of time and progresss marched inexorably on at Mullard's and an interesting development occurred for CRT in 1954. If you look at some of my earlier blog postings on the manufacture of CRT, you will see that the EHT connections provided pre-54 were somewhat different to those you may be more familiar with but this did indeed change in 1954.
If you recall, the earlier EHT connection comprised of a number of wires fused into the side of the envelope which was in turn soldered to a metal cap on the tube's exterior wall. To make such connectons required a fair deal of skill and the whole operation was labour intensive with Mullard suffering a trying time during 1952 when quite a number of these connections failed due to rough handling in transit which was expensive and wasteful - especially as the packaging for these early CRT was very good as well.
Anyhow, the replacement connector was a one piece jobbie made of a nickel-chrome-iron alloy which you can see in the photo below: -
And here is a photo showing the corresponding EHT connector - are things looking familiar now?: -
Item D was a handy little adaptor comprising of a thimble cap of standard dimensions, the lower end of which was fitted with six spring prongs to locate the terminal. This adaptor allowed TV receivers from past years to be rejuvenated with one of the newer tubes without changing the existing wiring - those chappies at Mullard thought of everything you know.