I believe the series may survive complete as it was on film. Certainly one episode survives as (I believe) Dick Fiddy turned it up and part was screened at a past MBW I attended. I seem to think it was later stated the whole run survived. I recall the series but can't remember The Sweet on it now. Good news!
Yes Lawrence rest assured if this show survives then there is at least one performance of AGB around. (probably a mime around a car park or something but better than nothing)
I think i saw this show when AGB had long been and gone and the Sweet were into their full glam blockbuster/blitz era . I thought what a strange thoughtful song for this manic band. Looking back though, they left a marvelous legacy of songs.