Really interesting photograph. I was intrigued by the man in the middle with the helmet with the light bulb on top and did a bit of investigating. There is a useful website which tells about the beginnings of the meteorological office - started in 1915 as a section of the Royal Engineers. The website is here
http://nigelef.tripod.com/fc_meteor.htm#World%20War%201I wonder if the helmet and the box between his feet are some kind of communications device for getting the weather information out to the troops - could be a field telephone. Haven't a clue what the light bulb is for. Someone who is expert on these things will, I am sure, tell you.
Also a couple of the men have wings on their uniforms and according to the above website, the Royal Flying Corps used to take the readings, send them down to the team on the ground, the information would then be telegraphed to the front. Again, there will be someone on Rootschat who will be able to tell you better than I can.
Good luck with your search - please let us know how it turns out.
Could the G R on the sign be for King George V.
Ruby