I remember the XO at Yeovilton had a crack down on the Zoomy pilots a few years ago for wearing their grow bags in Tesco. I think that he was General Service and got put out that they had nice leather jackets to wear and an abundent supply of Raybans (as per Top Gun). Plus, I think that it was the middle of the afternoon!
PS - What are the reg's for wearing uniform in London? (Harrod's notwithstanding as they have special local rules
)