Jeff Lewis – Answered:
George did ring Paul to ask him to participate at Madison Square Garden but the concert fell short only a three months after the big court case that effectively dissolved the Beatles Ltd. Paul didn’t understand why after fighting George, Ringo and John for so long in court he would jump straight back in to a Beatles reunion.
However Paul did say he would play if the three other Beatles signed a release from a financial document that was in place at the time.
The document covered all the solo material released by Apple up to 1975 and was evenly split among the four ex-Beatles regardless of the group no longer existing. As the most prolific and most commercial solo artist Paul felt he suffered the biggest financial hit.
This was around the time he started adding Linda’s name to the writing credit on Ram which had caused a war of words between Paul and John.