Complex sentence: The roof and the building's semi-circular sanctuary combine to afford an extremely attractive interior, whilst externally, the building's simple pointed style and use of local granite is also aesthetically pleasing and the building is perhaps most commonly described as,'pretty'.
Split into simpler sentences: The roof and the building's semi-circular sanctuary combine to afford an attractive interior. The building's simple pointed style and use of local granite is pleasing and the building is described as'pretty'.