Found whilst trimming my common ivy to house wall. Up to 10mm long. Colours and patternation varied depending on light and shade of photo's. Quite a quick mover on my brickwork. Deep red eyes and reddish antennae.
That's Nettle Groundbug: https://www.naturespot.org.uk/species/nettle-groundbug
Thanks David, a new species to me and i grow plenty of nettles too!