Yeah, I couldn’t name one either (I’m from the US). The first name that popped into my mind was Jimi Hendrix but he wasn’t British. I guess Othello wasn’t British either, and may not have even been historical. I had heard of Idris Elba but didn’t realize that he was British. No idea about the Spice Girls.
There is a story (maybe apocryphal) that former US Vice President Dan Quayle (famous for malapropisms) once referred to Nelson Mandela as a “great African-American”, fwiw.