Brian Connolly may have left in 1978, but Andy, Steve and Mick continued untill around 1982/1983. Then Andy & Mick reunited in 1986. Steve & Brian did some work with them in 1988 but it never went anywhere. Brian's health deteriorated quite a bit, Steve moved to America.
Mick left the band around 1991 due to ill health and Andy has continued ever since.
So I don't know which Sweet you're thinking of that called it quits in 1978? ;-)
I thought Steve Priest's Sweet had packed up? Seeing as Joe Retta, Stuart Smith & Richie Onori have all left to put Heaven & Earth back together?
Andy Scott's version, who have written and recorded new material and released live albums and toured regularly since 1986 are still going strong and have a very big following in Europe and oddly, Australia!
I really like Joe Retta's voice, so I look forward to what he'll do with Heaven & Earth, and that Sweet goes back to being Andy Scott's band again.
Niv