I started at the old London ATCC on the Northside of EGLL in May 61 as an ATCA. I well remember the old metal strip holders as I soon got caught by one Gerry Took, an ATCO who called out 'Here's a hot one' as he tossed me a stripholder, which of course had been sitting on the top of the old style cast iron Central heating radiator for 10 minutes. [ he wore a glove for the throw!] Oh happy days. En-route controlling was all done procedurally by the 'D' men. Us ATCA's wrote all the strips by hand and distributed them to the various sectors. I moved to Sopley JATCRU in 63 and spent 3 happy years monitoring the R/T and recording the flight data on 'edge lit display boards' with Chinagraph pencils. The radar was the long range RAF 'Type 80' with a pinhead size blip and the SSR was up to four short horizontal 'slashes' behind the primary blip. If I remember correctly the width and number of 'slashes' gave you the code. The Controllers soon learned to recognise their particular allocated SSR codes. No height read-out or callsign conversion or anything else in those days.