An odd place to find sandhoppers

Located near the entrance to Point Farm on the Dale Fort Road is a manhole containing the water meter for Dale Fort. While checking this the other day I disturbed a rock and to my great surprise several sandhoppers (Talitrus saltator) hopped out from underneath.  I've read of these creatures living high above the sea in caves and crevices on very exposed shores (subject to a lot of salty spray) but never in what I'd consider a purely terrestrial habitat.  Given the location I suppose there's a strong maritime influence.  Nevertheless, the site is about 30m vertically from the sea above what is a very sheltered shore.