"Not sure if the building on the right is the spectators building or the domestic terminal"...
Nice retro shot...
The building on the right is what was referred to as the "Executive Terminal" and was lightly (or never) used as such. It was certainly used as an exhibition area for Airport open days around that time as I recall, and I remember using it (with a hi-lo provided by the Airport) as a back-drop in a photo-shoot for a Vauxhall piece I did for a motoring magazine in 1994-ish...
It was of course later passed over to easyJet when they started Ops at LTN, expanded / painted orange and has been referred to as "easyLand" ever since.
Interesting that there is no sign of the Spectators' Building in this image. That was situated to the left of the Exec' Terminal in this picture - and thus clearly hadn't been built then of course.
When I started working at LTN full-time in 1996 "Speccies" was there and in use (but not much it has to be said). Apparently none of the operators that took the lease on the Cafe and Bookshop were really able to make it pay, and I especially remember that the "Spectators' Car Park" situated there had some very dodgy entrance barriers which worked on a token system and which were easily errmmm... 'manipulated' - so little revenue was generated there either. Hence it's eventual demise
Fast Eddie