By the early twentieth century it had already been reduced to what one observer described simply as a closed-up cave, the original purpose of its construction long since obscured.

The earliest written description comes from Seymour in 1912, who recorded only that the structure was sealed. Half a century later, in 1960, the archaeologist Etienne Rynne visited the site and noted it again as a cave, suggesting that at that point something remained visible or accessible, if only barely. The hillock also had a mound associated with it, hinting that the souterrain was not an isolated feature but part of a small cluster of early activity on this slightly elevated ground. The position made a certain practical sense: a modest rise with clear views over the wet, poorly drained bogland would have been a defensible and dry-ish foothold in an otherwise difficult landscape. What the full extent of that early settlement looked like is now impossible to say, because a large quarry has since consumed the area entirely, removing both the hillock and whatever archaeological remains it once held.