Uniform Wednesday is, I believe, still practised in Main Building. If it was made de riguer a fortune could be saved (both by the Budget Holders and the SP) on having to subsidise Oyster Cards.
I travelled a number of times on the Tube in a variety of uniforms - No 1s, No 2s, DPM, Mess Kit; nothing was ever said apart from a tourist (Canadian) who thought I was 'Royal Artillery' - I was returning from Uxbridge CCS and my back-pack strap covered 'Air Force' on the silly patches we had above our pockets on CS95. He was very pleasant, slapped me on the back and wished me well. However, I know that some women personnel are not happy about travelling in uniform - and that's understandable.