Iridescent blue-green 'woodlouse'????

Observation - Iridescent blue-green 'woodlouse'???? - UK and Ireland. Description: Woodlouse-sized, startling brilliant blue-green, pulled in tiny rectangular head and thorax when disturbed, domed body contracted - body soft and deeply wrinkled rather than having separate plates. Thin adult-insect-type legs. Seen in daytime on Pembrokes

Woodlouse-sized, startling brilliant blue-green, pulled in tiny rectangular head and thorax when disturbed, domed body contracted - body soft and deeply wrinkled rather than having separate plates. Thin adult-insect-type legs. Seen in daytime on Pembrokeshire National Park Coastal Path creeping across short grass.