As Discord says the ill fated Papa India would have crossed Epsom as its first waypoint out of LHR on what in those days I think was a simple Dover One departure, I think the first SIDs were in use by then. Earlier than that one could listen to LHR departure controllers issuing the whole Instrument departure for each aircraft which was usually something like cleared IMC to XXX cross Epsom above two (thousand) Biggin above four and something along the lines of climb as directed by radar . A long time ago when nice neat looking aircraft like Swissair Convair 440s used those instructions to head off to Zurich. A bit of a joke these days as an A320 series departing on an LHR westerly could probably make about 8000 ft by Epsom if it was allowed. I must admit I thought Epsom disappeared as a beacon when Ockham VOR was activated and became one of the LHR holds. The past year must have been odd for folks who live underneath the LHR holding patterns as they probably haven't been used for a year depriving the good folk of that pricey part of the outer London area of their early morning wakeups from the Atlantic inbounds wending their way around the Ockham pattern