As mentioned at start of the thread, it's in the ETI Nov 1978: With full copy here:
https://worldradiohistory.com/UK/Ele...1978-11-78.pdf
The Centre for Computing History website, list several manuals & Mag. articles
http://www.computinghistory.org.uk/d...ransam-Triton/
And has them to download - But unlike the MK14 ones, you have to pay a few £'s to download each.
Gerald's put the VDU IC datasheet, amongst others on his website for this:
https://sites.google.com/view/transa...ets?authuser=0
I do have an odd video board that has an EF9364AP DIL28 IC on it, that looks like it may well be an equiv. along with the same 1.008MHz crystal. I haven't worked out what the board was for, but only cost me £1 (rather less than littlediode's price for that IC!)