Thank you all very much for the kind identification (and pointing out the embarrassing flip in the image) - after a time there is a risk of blindness when the source material is on transparency or negatives. I'd blame the heat here
It is slightly more embarrassing as I did react to the air bridge being on the "wrong" side this morning when I first read the identification response, but I had a vague recollection that a couple of North American airports had done that for some reason or another and just thought that this was one of those strange things, all that time ago (the picture was taken circa Aug/Sept 1974 according to the limited information to hand.
Again, thank you!