The three Initial training wings 10,11,and17 at Scarborough provided basic training in aircraft mechanics, navigation, meteorology as well as square bashing and PT specifically for potential aircrew (pilots ,navigators and bomb aimers). (google to confirm this). The men in naval uniform must therefore be potential aircrew of the Royal Naval Air Service, who would need the same sort of training before going on to Elementary flying training. Free French, Polish and Belgian Air Force Trainees also went to Scarborough
http://www.raf-lichfield.co.uk/GroundUnits.htm This reference shows the three ITW's ceasing to exist in spring 44 but I believe this was just a name change because of the the impending closure (jul 44) of the Aircrew reception centre at Lords CC RAF St Johns Wood and the dispersal of the ACRC responsibilties to the ITW's I think that 17 ITW became 36 R&C Wing. (R = reception)