Found on the sand, i put it in a rock pool.
No interactions present.
Thank you for your ID help.
It certainly looks like a Butterfish and seems to match the images on the carousel.
Chris Brooks - www.dragonfly-images.co.uk
My Flickr site - www.flickr.com/photos/ceb1298
It's the only eel-like uk fish with this row of black spots
Lat/Lng: 54.7, -4.6
OS grid ref: NX3344