Complex sentence: The decision to build shops into the front of the building was taken and in 1895--96 three shops were added to the ground floor in what had been the library and committee room provided much-needed revenue for the SMSA which was otherwise in decline.
Split into simpler sentences: The decision to build shops was taken and in 1895--96 three shops were added to the front of the building on the ground floor in what had been the library and committee room. The shops provided much-needed revenue for the SMSA which was otherwise in decline.