Complex sentence: Since construction and prior to the construction of the new Bullring the Rotunda had advertisement signs on the top of the building this was in the 1960s and 1970s the property company MEPC and latterly in the 1980s and 1990s the Rotunda had displayed signs for Coca Cola.
Split into simpler sentences: Since construction and prior to the construction of the new Bullring the Rotunda had advertisement signs on the top of the building. In the 1960s and 1970s these advertisements were for the property company MEPC, while in the 1980s and 1990s the Rotunda displayed signs for Coca Cola.