Talking of diversions - early 1970 the firemen at Heathrow going on strike/work to rule resulting in not enough cover at certain times of the day especially early evening. British European Airways, Northeast, Sabena, KLM, Aer Lingus etc landed at Luton dropping off passengers and then positioning empty to Heathorw hoping for the fire cover to come up to the required status.
Also in the 1970s firemen at Gatwick went on strike just before Christmas (I think Christmas Eve) and Dan-Air, Laker and BIA aircraft were parked all over the place including the Bravo taxiway! Perhaps Vintage ATCO can verify?