Mighty Soul Rebels

London based Roots Reggae harmony group, The line up was Melvin Dockeray, Leon Lieffer, Brentnall Solomon, Dennis Dailey and Barrington Thomas, Founder member [a=Leon Leiffer] went on to be one of [a=The Blackstones]
Presumably, the label [l=MSR (5)] belonged to one or more of the band members