Hi Mike,
I'm coming to the conclusion that it was a bit heavy and shifty wind wise for the boat, you're quite right, it's much smaller than the Thunder Tiger Victoria I had intended to buy "can't get one of those at the moment sir, how about one of these?"
If memory serves me correctly, it was turning to wind under a gust.
I'm going to repair the sail simply my stitching the hole closed with some cotton, perhaps not quite ideal, but it'll allow me to use the boat again before making other drastic changes