Further to the quality of army vs airforce uniform issue -
After ww2 Dickins and Jones of Sloane St were selling US army airforce surplus battledress tops and trousers - being almost identical to British issue with the big difference that the US quality, cut fit and attention to detail were absolutely superb. Photos exist in various books showing the late General Montgomery dressed in US ARMY kit although most probably assumed the photo showed him wearing British issue. Not sure if present day items of US airforce issue would match RAF shades but there may still be a well known forces surplus store near Euston Rd that may be worth a visit for some items.