John D.
I was in the audience at this concert, and I can tell you that it was not cancelled - it was abandoned halfway through.
The Cure played their complete opening set, followed by an interval. During the interval, some right-wing thugs in the audience started causing trouble, shouting Nazi slogans and making Nazi salutes. Siouxsie And The Banshees came on and started to play their set, but the thugs' obnoxious behaviour got worse. Siouxsie remonstrated with them several times, to no effect. Eventually, the band walked off stage mid-set and never returned. The gig was abandoned.