Badges etc certainly look like Army ones...but...The RAF came out of an Army Regiment, the RFC, so rank badges amongst the ORs were at that time the same...The WO has the same rank badge as some RSM photos I have from WW1.
I really must beg to differ that this is a WW2 photo. Not only are the uniforms all wrong, the chap in civvies must have fallen through a time portal or is some sort of re enactor who likes to dress some 20yrs behind the times...

The types of shirt collar worn on the pics are also earlier than WW2...I am aware of "make do and mend" but that would be taking it too far....
Back to our swarthy friend...I can discern no facial features that would indicate an ethnicity other than North European Caucasian...nose, ears, bone structure all indicate this....
I would also suggest that the pic is "genuine" and that it is one of those "joke" pics that servicemen have a habit in taking...I have loads...
As you suggest that..
"the headphones are definitely WWII vintage and
possibly earlier, the style and the woven cabling is a giveaway there..."
This would fit in with the earlier comments from myself and flakdodger where it is proposed that this pic is from 20s/30s
The RAF at this time was a fledgling organisation and of course variants existed between squadrons as local tribal distinctions were still evident.
If the story is unknown to people...The reason why the RAF went into blue is that when the Russian Revolution took place, an awful lot of orders were canceled with various suppliers...one of these was for uniform material...Russian blue!! This was then given to the junior service!!!