Complex sentence: The interior was destroyed by bombing in the Bristol Blitz of 1940 and rebuilt in 1974-5 as a church museum, which has now (2007) closed and the building is used by the city council as offices.
Split into simpler sentences: The interior was destroyed by bombing in the Bristol Blitz of 1940 and rebuilt in 1974-5 as a church museum. This closed in 2007 and the building is now used by the city council as offices.