Complex sentence: It is 10.3m high at its apex and 11.3m from wall to opposite wall and was substantially re-built by Bishop Andrew Stewart (1482--1501) whose coat of arms is placed on the central pillar.
Split into simpler sentences: It is 10.3m high at its apex and 11.3m from wall to opposite wall. It was re-built by Bishop Andrew Stewart (1482--1501) whose coat of arms is placed in the central pillar.