I tried the mat and fine 'wet and dry' paper technique. I think I may have pressed down a little too much when pushing the edge forwards into the paper (I usually use an oilstone) so I may have rounded off the edge by pushing it into the mat rather than sharpening it... The black coating was abraded a little upto about 2/3 mm from the edge and the edge itself was lovely and polished shiny but DULL (a steel made no real difference, still deadly dull). On my stone the time spent would have got me a nice sharp V profile, my Scrapper still resembles the banana previously lamented! I think I may go with the stone on this one... (Just to gets my facts straight is the main benefit of a convex edge a little more chip resistance or something else?)