Treadigraph- wellI am a bit older than you -born 1954 so i did see alot of piston engined stuff- and i lived right next to LHR when it had four working runways . So i consider myself lucky as an enthusiast having seen airliner development to the point that its all just a big/giant 737 these days.
Anyway the main point of my post was that like you I could exactly as you did instantly identify everything -in some cases even from just the noise-Coronados/990s especially odd sounding .
Living in the South west now I still cannot give up looking at contrails although over my way the predominant flights are KLM to the Caribbean and S America barely ever anything BA very occasionally a 777 or 350 descending through about 17000 above Bath inbound to LHR