Discorde, you are right. For many years the Fire Service practice airframe . I used to remeebr the registration but no more . It was scrapped when they built the 747/DC10 combo green giant that lived on the Engineering base area east of 23/05. This had gas fuelled fire areas and was needed by the time it was built 1990s?? since there was very little on an Argonaut that was in any way like a modern aircraft especially a widebody.
I grew up in Stanwell south west of LHR as a kid and my earliest spotting memories are of eastbounds departing from 09R in the days before it was fully extended to the present length and I can still remember the appalling racket Argonauts made on take off compared to the much smoother sounding US radials. The Merlin was a wonderful military engine but for civil use it must have deafened hundreds who flew in it . Presumably it was some sort of economy meaure to save $$$ on US proper civilian aircraft as most of our post war piston aircraft were pretty dreadful and pretty dangerous until the Viscount came along and the finally fixed Comet 4.. I never flew on a big piston but I think the difference between them and the Viscount for noise and vibration must have been the biggest step in pax comfort ever. I was lucky enough to fly on a Viscount a couple of times and it really was a nice ride pretty much the same as one gets on a A320 today. Scuse the thread drift