Being ex-SATCC, I remember the RAF radar unit 'Heathrow Radar' there when Garston was Leavesden 'LEA' (112.3 ? M/cs). Before that it was Watford NDB 'WAT' on 279 k/cs.
'Leave Leavesden heading.......' was a bit of a mouthful.
Is anybody 'London Radar' or 'London Airways' any more?