The chapel was shrunk by the insertion of two side walls in the 12th century restoration, and thus two narrow rooms were created, the doors to these rooms are in the side walls. The left hand wall reaches the ceiling and has three round-headed apertures high up, but the right hand wall is only a screen and there is a wide gap between its top and the ceiling. When the monastery was inhabited by Paulinian monks the right hand room was their choir. The left hand room is the church's sacristy.