That's some good digging Coff!
That kit shown above (and on page 7 of the linked document) was the old oscilloscope version we used for transatlantic routes. It was all a bit 'black magic' but basically worked around capturing a signal and then locking the third-cycle (the make a fish exercise).
I recall being on a route which grew like topsy and involved us taking fairly long breaks at out-of-the-way USAF bases and occasionally popping back to airfields we thought we were done with. At one stage (having been re-united with my suitcase which had been offloaded on the first flag stop at Lajes by a junior Loadie on a thinly disguised chop ride with STANEVAL), both navs had reverted to the feral state. Whilst waiting for our flight plans back to Lyneham to be accepted, we broke up the monotony of watching episodes of Mr. Rodgers in Flight Planning (it's a beautiful day in the neighbourhood) by having competitions to see who could sprint up the crew steps, fire up the kit and make a fish fastest. The result was a draw as it was subsequently proven that we were both clinically insane.