Dan Air check in desks
The original terminal check in layout, which was retained until 1984, had all the check in desks facing the entrance doors, with Autair on the left, Britannia in the middle and British Midland on the right. I believe Monarch desks when they appeared in 1968 were between the Britannia and Midland desks. Dan Air check in was indeed located at the back of the Autair desks facing the other way until the collapse of Court Line (Autair), when they took over their check in desks. Channel Airways had a single check in desk at the right hand end during 1969.
A correction to my previous - Dan Air closed Luton as an aircraft base a few months before they closed it as a handling base in November 1979. Their limited programme during summer 1979 (3 flights a week if I remember correctly) was operated by Gatwick based aircraft on W-patterns. Most of their 3rd party handling business, plus their own flights, transferred to Monarch who became the main handling agent at the airport; Britannia being the other one. Also, the 1st Dan Air Comet to be based from 29/3/69 was G-APDO not G-APDN.