If I remember correctly when British Eagle went bust in November 1968 both Britannia and Monarch - which took on several Eagle Britannia's and many ex-Eagle crews - operated the vast majority of ski flights from Luton in early 1969 which should have been flown by Eagle from Heathrow.
When the two ex-American Airlines BAC-111s arrived Dan-Air decided to base them at Luton flying mainly for Lunn-Poly and Everyman Tours. They set up a handling facility at Luton with the ground equipment which included a bicycle and a green Mini van with a 'DAN-AIR LONDON' sticker emblazoned on it (many interesting stories abound about that van).
As regards the AA 1-11s a good friend of mine worked for Dan-Air handling at the time and as he was putting the chocks on to the nose wheel tyres the captain shouted down to him and I quote 'I have never flown such a load of s**t in my life' as the passengers were disembarking down the front passenger steps.
Comets also began to appear at Luton on an ad-hoc basis and Gatwick diversions.