Thanks for the advice Darryn. I capsized in 15knots with 20 knot gusts on Saturday. I swam the boat down wind of the rig and uncleated the main and traveller. I climbed onto the hull and remembering your post above simply pulled the dolphin striker stap and she came straight up. At right angles to the wind I had to hold on tight to stop the boat tipping straight back over.
In all, I lost less than 4 minutes and came 3rd out of 19 boats which is good for me in a club race (although I should note we had 10 boats DNF )