Interesting view of the civilian route to the rhs of a large company passenger fleet. Presumably, a similar path was trodden by the BEA hopefuls. Their fleet included the venerable Viking, which was employed in a similar, but generally more demanding role by the RAF Valetta. The interesting bit is that our route to the rhs was " Right - you're it !" The Signaller (Radio Operator)_was designated right seat for Take-off, Landing and en-route pilot breaks. Depending on the Skipper, you may have been given some 'one-off' handling time, but, otherwise it was 'watch and learn'. Since the designation included potential aircraft recovery in the event of pilot incapacitation, there was considerable impetus to 'upskill' !
I've often wondered if the results of the (in those days) Hornchurch 3 day testing was the decider as to who went to Transport Command and who to Coastal ? The process was a fertile 'breeding ground' for 'crossovers'.