Cheers Daragh, good link.
If anyones interested, there's a DVD available of that legendary English tour. It features Otis, Sam & Dave and Booker T and the MG's. Its rare that TV cameras can capture the real excitement going in in the venue, but they manage to do it for this show. Its a seriously good concert. I think it was shown on the BBC a few years back too.
Also, Peter Guralnicks Sweet Soul Music is definitely worth a read. It traces Stax from a haybarn in rural Memphis to the massive WattStax concert in the mid 70's.