Almost a year after their return as one of the unexpected hits at Glastonbury, when such a crowd turned up that entry to the Avalon gig had to be shut to any more fans, Sugababes brought their summer festivities to Belfast on Friday night, as part of the Live at Botanic Gardens series of concerts. While I never had the joy of seeing them the first time around (my hero then was Morrissey as opposed to fun pop girl bands, but sure, we live and learn) I can’t imagine that this original line-up, known for some years by the altogether less…