bjornWA8 said..
Thanks for all the advice. Much appreciated.
I'll pump it up inside to check for twisted bladder. If looking ok I'll then swap the bridles around to see if it starts to pull the opposite way during the next session - there is about a 0.5 to 1.0cm difference in one of the 29cm bridle lines, which I thought was not significant, but by the sounds of the above it may be. When I had the kite pumped up before inside, it didn't look to have any obvious twists and the canopy didn't look stretched, but I'll take a closer look at the stitching next time, and also sit the kite on the trailing edge.
Its not a twisted bladder thats just not possible. The bladder would need to be removed and refitted incorrectly for there to be a full twist in the bladder. The bladder is a very thin and flexible material and would not be able to exert enough pressure on the dacron LE tube to affect it.
Most likely cause is that bridle length asymmetry. If the kite copped a decent pull from a wave then thats the likely cause or the other cause I've seen over the years is the Dacron LE has been stretched out of shape especially if the kite was wet when it was bagged and stored (so it dried with the twist/stretch in it). Replace stretched or shrunk bridles, or try wetting them and stretching the opposing legs together between 2 nails in a bit of wood.
If that the case inflate and wet the kite, twisting it with a helper to get it sitting as symmetrically as possible and then let it dry indoors.