I firstly scored where I wanted to part the hard outer covering. Coil is dead so no worries about the outcome.
It took some punishment from a Stanley type knife to break through.
The outer part appears to have been a simple Tufnol or Bakelite tube, added after the end bobbin type pieces.
Wrapped up like king tut I think, with bandages and resin, it did a good job, I have found others in awful states where water has got in and HT windings are just a lump of blue copper oxide. The connection here is often where the trouble is, folk trying to save time and money by soldering onto this little plate often melt the HT wire away, be warned.
It's a small task to get to the actual wire, this one was well made.
On later models, a piece of very high insulative mica is used, like this inch square piece.
Finally got down to the first row of very fine wire.
Like a hair from your head, or even thinner, it's amazing that makers could wind thousands of turns and many layers of stuff like this without a break or shorting out anywhere.
First check that micrometer reads zero.
Then isert wire Then insert wire and gently tighten up jaws.
2.5 thous of an inch, I doubt I could manage to wind such frail stuff, even in my younger days when my eyes were good.
The HT connection, in all of its glory.