Thankyou, bean and H49. To think that the 1-11 500 was the aircraft that Sir George Edwards was trying very hard to persuade Britannia to buy; they were having none of it and the rest is history. A wise decision too.
Aer Lingus used early turbojet 720s on Shannon - New York and Monarch used the fan version on Caribbean trips, albeit with a quick splash and dash in the Azores. Neither variant was a transatlantic machine but Mediterranean trips from the UK and Ireland were proven quickly. Again, departure runway length and takeoff distance and run etc. were highly significant. Bristol Airport had a slightly longer runway than LBA prior to 1984 and 720s and Monarch 1-11s weren't unknown there. Jersey, I understand, has a cliff at one end of its runway. Nice!
I didn't realise that lower air temperatures were a deciding factor in scheduling jet departures from limiting runways in the summer. Makes sense now. I know the Viscounts used to struggle sometimes, even just going to the Channel islands. The 757 never had this problem, even off a short runway. I well remember that first visit from a Monarch 757 - a very capable aeroplane.
I forgot to mention Air Malta in my earlier posts. They too operated their new Advanced 737s to and from LBA in the early 1980s, usually in the winter evenings IIRC. Quite a distance to Malta launching off a short runway, further proof of the A737's superiority. I'm reasonably certain LBA never hosted an Air Malta Boeing 720B.