Complex sentence: When the BBC left around 1976, the theatre went dark and was in danger of demolition, but it was saved and restored to its 1907 design by impressario Robin Gonshaw, opening again in October 1987 with the musical "Girlfriends".
Split into simpler sentences: When the BBC left around 1976, the theatre went dark and was in danger of demolition. The theatre was restored to its 1907 design by impressario Robin Gonshaw, opening again in October 1987 with the musical "Girlfriends".