Great fun !
The Comet, and BAC 1-11 were all very much in the first mix, and I did doubt the 727 in my very first post #21
but looking more closely at those large LE slats of the 727 were the thing that got me going on the 727 as the aircraft in the photo.
Condor DE (who had 7) and Transair Sweden TB (with 3 in the fleet) had both been flying their holiday 727-100s since the mid 1960's.
In 1973 both Dan Air DA and Hapag Lloyd HF were new to having the 727-100 for the IT market, both airlines having obtained secondhand examples from Japan.
Dan Air would take 5 and then have these modified with 2 extra rear exit doors to enable up to 154 passengers to be carried.
These would be based at LGW and MAN, but also flew from LTN BHX GLA MME NCL TXL and BOH gradually replacing the Comets on the longer routes.
DA would soon obtain 3 more without having the door mods that held 131 passengers which would often be based at Berlin TXL flying West German holidaymakers.
HF would also take 8 (some ex ANA TDA and JAL and one from Sabena)
No other holiday airlines modified their 727-100's with extra exit doors.
BMA and Britannia Airways both had considered the 727-100 early on as a future type and were close to placing orders.
Possibly the most prolific charter 727 seen from 1966 at LGW was the 727-11 of Wardair.
This 727 was used to 'sub' for other airlines whilst on down time at LGW or MAN, and flew me DBV-LGW on behalf of BCAL in August 1972.
The Pan Am 727-21's based at Berlin TXL for the IGS routes, were used at weekends for IT Med charters for West German holidaymakers.