The site is associated with St Patrick's Bed, a monument on the hill that has long drawn attention, but it was the invisible archaeology surrounding it that proved surprising. Geophysical prospection, a non-invasive technique using instruments that measure variations in the soil's magnetic properties and electrical resistance, revealed two previously unrecorded enclosures that no one had documented before.

The larger of the two enclosures, identified through surveys published by Dr Roseanne Schot in 2005 and 2011, appears as a narrow circular band of enhanced magnetic values, between 0.5 and 1 metre wide and roughly 35 metres in diameter, curving around the south of St Patrick's Bed. Within that band there are hints of a second, concentric arc sitting 3 to 4 metres inside the first. Resistance survey, which measures how easily electrical current passes through the ground, mapped the same feature as a discontinuous ring of low resistance values. Taken together, these signatures point to a palisade trench, the kind of narrow slot dug to hold upright timber posts forming a fence or enclosure wall, rather than an earthen bank. There appear to be two gaps in the circuit: a less defined one on the eastern side, and a more clearly articulated opening of 1 to 2 metres on the south. From that southern gap, two parallel low-resistance lineations extend outward, spaced 3 to 4 metres apart, which Schot interpreted as a formal entrance feature. St Patrick's Bed sits just north of the enclosure's centre, and the larger enclosure itself overlaps with a second, smaller one of similar form that may pre-date it, suggesting the site accumulated layers of use and meaning across more than one period.