Danny, thank you for describing "how it was done" so graphically. The means by which tracker told Talkdown how the customer was performing vertically was both simple and ingenious, given as you say all the talking had to be done by the latter. I've been Googling around to try to find a picture or diagram of the set up but no luck yet.
I have come across this though, yet another Canadian contribution (are they more caring of their history than we?), which lists the UK airfields "Bendixed" during WW2:-
http://67.69.104.76:84/rcaf-atc/othe...other-16n.html