Measuring barely a metre and a half in length, it is thought to have functioned as a latrine, a practical reminder that the people who used these buildings had thoroughly ordinary needs alongside their spiritual ones. The annexe itself was not built at the same time as the main church; it is unbonded from the primary wall, meaning it was added later, stitched on rather than growing from the original structure.

The church itself is a slender east-west rectangle, roughly ten metres long and just under four metres wide, with two doorways still discernible: one placed centrally in the west gable, the other near the western end of the south wall, opening into the annexe. The whole thing is poorly preserved and has seen considerable conservation work over the years. Peter Harbison, writing in 1975, dated the foundations to somewhere in the eleventh or twelfth century, making this the oldest building on a site that also includes a nearby structure known as the Nunnery, situated just ten metres to the north. Inside the church, a medieval graveslab survives along with what appears to be the head of a window, its tracery or moulding now unreadable. Two cross-slabs are also associated with the site; cross-slabs are flat stones carved with a cross, often of early medieval origin, and here they add to a sense that the site was in continuous use across several centuries. The monument is now a National Monument under State ownership.