Well that one's certainly tested my googling skills!
HMS Shipham looks to be a good candidate to me. Although she was first launched on 14/07/55, she wasn't completed until 03/02/56, by Brooke Marine of Lowestoft. She was named after a village in north Somerset, and sold in 1986.
So now all that's left for you to do is to compare your picture with this one:
http://www.shipspotting.com/gallery/photo.php?lid=33859
Chris