I came across your forum a few days ago. I reside in Australia and my father Fred Brown (his nickname was Ferdie - hence my forum name), was the owner skipper of this vessel when it was lost in 1957. Fred is thankfully still with us and enjoyed seeing the photo. He and his mate Ken Splaschet were on board and on their way to do a recovery of a German Patrol boat that had been purchased for a conversion for living. Again thankfully they both survived.
BM81 was operating out of Leigh-on-Sea after being bought out of Brixham. If anyone is interested I do have a couple of other photos as well as the paper article when they were picked up at sea following the sinking. If anyone would like them posted I will arrange for that?
Cheers for now ... john Brown