A brief search among the abundant mussel shells along the strandline should reveal some with hairy tufts. These were found at Rock-a-Nore ,They look like fine, dried seaweeds but are in fact the remains of colonial hydroids and are , or were, animals. There are lots of species like this in British waters, the excellent “Collins Guide to the Seas
hore of Britain and Northern Europe has several pages devoted to these and I can’t tell what species this is. When alive, it seems that short tentacles emerge from ends of the branched parts shown in the enlargement.