This might not be the "O'Mahoney's" you were expecting (as if people sit around expecting hornpipes of whatever name) but I noticed it under this name in "Ceol Rince na hÉireann Vol 2. I always just called it "do you know this one?". Brendán Breathnach took it down from Denis Murphy's playing for CRÉ 2. I'll go with the present name as I always believe what other people have written.
Nice job. When I learned this we called it the Hatter’s Hornpipe,but I prefer your name of “do you know this one”!!