Servisair that set up shop at LGW was a very different beast to the old S-Aair at say MAN from the 60's
At LGW they bought in to or took over Ogdens' handling (who in turn had taken over BA's 3rd party handling in 1988 after the BCAL takeover)
LGW handling back in the day (my day lol) was GHL (owned by Dan Air and Laker) BEA then BA, and BUA then BCAL - that was it until BA took over BCAL and Ogdens came in)