MPN11,
And the Type 13 "Height Finders" ! Remember they had one at RAF Fazackerley (Liverpool) when the "Volunteer Reserve" restarted after WWII, and I rejoined as a Flying Officer.
On the other side of the nearby wire fence, a knot of spectators would gather from time to time to gawp at the "Nodding Donkey". We would give the operator a buzz, he would swing it round pointing at them, then nod up and down menacingly. Cleared the crowd in moments !
How we laughed!...... Danny.