This is the place where Stones fans can advertise anything for sale, wanted, trade or whatever, from fan to fan. Advertisements are for free. To see the old ads go here.
As far as I know John Mayall played the Newport Jazz Festival on July 5, 1969.
According to James Karnbach's book (and other sources) the supporting acts at Hyde Park were Third Ear Band, King Crimson, Screw, Alexis Korner's New Church, Battered Ornament and Family.