Just wanted to say thanks to all the testers for their feedback, which I have copied to a word document with my settings for reference. Several people were saying my ride was a bit blobby - when I submitted it I knew that my spring rates were considerably less than everyone else's! I think my eyes crave the body pitch and roll as feedback on the amount of force I'm generating - but there obviously comes a time where the car is too mushy and slow to respond.
I bit the bullet and upped all springs by 20% - still quite soft - but now the quick weaves after the fishbowl feel a lot more controllable and therefore my braking for the following sharp left hander has improved. Before, that section of the track always felt like a rollercoaster just as you go over the top of a hump.
I've not touched the ARBs so I've probably affected the balance a little, but if it has changed it's certainly not for the worse, a little looser perhaps.