When I first started BS the colour was actually purple/lilac, then along come BV which in lilac, and BS seemed to change to grey/silver. Recently some if not all the programmes have varied colours, perhaps for variety, BS has had pink, light blue, BB/BF has had pink, but mostly they have stuck to the official colour for the programme.
I believe the official colour for BS is grey/silver.
Happy Stepping
Always Be the Best You Can, Never Ever, Ever Give Up! Dare to be Different!