Yeah it wasn't budging with anything, so a screw driver it was! There isn't much room to work either, just enough to get my arm down the side and the filter is tucked in close to the engine as well. So two seperate punches and she finally threaded off. And up, I only hand tightened the new one
Done many many a oil filter change on a car back in high school auto class. I just wanted to be sure there wasn't something odd at play here seeing as it was on so tight.
All is now happy in the land of Westerbeke Oil changes
Thanks again folks!