It seems there were alot of British bands that started playing "blues" and then migrated to pop/rock. Jethro Tull and Led Zeppelin are two that come to mind. I like early Fleetwood Mac, but I also like the later incarnation. Same goes for Led Zeppelin. Jethro Tull's first album, the bluesy, jazzy, "This Was", was excellent. Their second was good, third, not bad and fourth, "Aqualung" is overated in my opinion.