Would love to try but the DVLA have withdrawn my licence for 2 years following brain surgery.
The "castle" is a mystery; it seems a bit barren and Gibraltar, or maybe the Channel Islands are possible candidates - I have tried "military look outs" etc with no success and have to go out soon. (Wife as chauffeuse ) . This is a hard one.
Maybe this is an "unsolved "one? Could it be in a N African country like Morocco or Tunisia where there were "castles" and the dress was more "relaxed"? I have scoured Castles, Observation and Lookout points in Oman, Dubai, Tunisia, Morocco , Aden, Channel Islands and admit defeat for now! The dark men in white with white clothes and headgear are puzzling.
I think that the soldiers? (there are quite a few) are, indeed, Sheikhs in white uniform , and that the top "hut" is some sort of observation platform (No signs of guns). The "castle" is puzzling and hints at a developed country (maybe a former colony, like India). Sheikh troops were a feature of the old Indian Army and a possibility is that this is an outpost in another country altogether but manned by them.