Chugalug,
Be pleased to know that you fooled a youngster many moons ago.
One of the things that got my interest in aircraft going was the use of a suitable radio and I do recall hearing the "Chugalug" calls.
Being only lad of minor age then I always thought that it was some foreign word of greeting like "hello" or "good morning" in a native language.
Well I suppose I was almost right.
MPN11,
Border, Midland, Eastern. All bring back some memories to a young lad trying to figure out what some sayings meant. Did mange to get a few right but others were way out when I did find out what was the correct meaning.
Remember hearing some helo formation call "Calcutta, Calcutta, Go" to later find out it was a call for all lights out. Suitable touch of military humour I thought.