Back in 1998 at the Long Beach Blues Festival, we were treated not only to a great set by the Splinter Group, but a great "British Blues All-Stars Jam"
Peter Green, Mick Taylor, Kim Simmonds, Nigel Watson, Ronnie Earl, Buddy Whittington-guitars
Peter Stroud (Splitner Group)-bass
Joe Yuele & Jim McCarty (Yardbirds)-drums
Keith Emerson-organ
John Mayall-vocals, electric piano
So, there's precidence for Mick & Peter playing together with Mayall.