According to Jesse Jarnow " the original contract shows 5 nights at the Rainbow at the tour's start (April 5, 6, 7, 8, 9) & 3 more shows at the Rainbow at the tour's end (May 26, 27, 28) replaced by Empire Pool when the Rainbow closed"
Anonymous comment to JGMF via comment to JGMF tour opening London shows "1972-04-05 to 09, the London shows to start the Europe 72 tour were intended to be at the Rainbow Theatre in Finsbury Park but the owners went broke. The shows were switched to tne Commodore bingo hall in Hammersmith but Cutler thought that was too small so the Dead played the two nights at the Empire Pool in Wembley instead, McNally p 425."