Just for interest, when I first started at LHR in 1978 there were four Marconi 264H radars, one Cossor ACR6, one Plessey AR1 and one Decca ASMI surface movement radat. When I left in 2010 there were two Raytheon ASR10's and four Terma SMR's plus two Qinetic FOD radars, and they all worked magnificiently despite my efforts and harsh language.