Derby's first colour scheme was a minimal modification of BEA's at the time. The 3 maroon cheatlines were simply changed to dark blue on the ex-BEA Daks.
The second scheme was dark blue and what I would have called turquoise but could be deemed light blue. I think this was the same shade as used on the Chipmunks ?
It was while this scheme was in use that the name was changed to BM, and the colours were I believe retained in the next scheme. Don't remember any black though, except for titles.