There is some very interesting work surrounding this on Professor Simon's YouTube channel, where amongst other things, he is getting help from people who are going to find the site of the photo. (He is from Scotland; Calvine is in Scotland.)
David Clarke - who tracked down this original photo after decades of work - has had some expert analysis done on the photo. Long story short; it was taken on a suspiciously good camera for young lads working as washer-uppers in a local hotel.
It's a fascinating story when you take into account the political situation at the time, the jumpiness of British and US military just prior to the first Gulf War, the location, how this particular photo was found, why it never got into the local paper and why the photographer(s) vanished. There is a name on the back of the photo which is assumed to be the photographer...
I suspect *if* it's a clever hoax, or misidentification of a rock in a nearby reservoir, or some other prosaic explanation, it's quite likely the photographers really want to keep out of it now considering all the fuss they've caused!
Prof Simon's YouTube videos (nine on this subject at the moment) -
Video of David Clarke in discussion with other Calvine researchers. Some good links including photo analysis -