Decca navigator
The Trident did have a moving map. Your position was where the pen nib was.
The map moved up and the pointer (pen nib) moved side to side. Initally the pen had ink in it so you could see where you had been, but, having used it the map was then unusable, so very quickly the ink was not replaced.
I think thouge the first Decca Navigator was fitted to the Viscount. This worked in the same way but the vertical portion of the map was only about a third of the size of the one on the Trident.
When the Russians (Aeroflot) started flying in to London in the early 1960`s they had a couple of TU104`s fitted with the equiptment. They refused to rent them from Decca, the same as everybody else who used them did, but actually bought two complete systems. As a result they normally could only use those two aircraft into the UK.