Thanks for all the suggestions guys. I'll try to respond in one...
Gregg - you're right, toe out encourages the car to turn more. So toe in isn't to blame here.
Krait - standard Harrison (Holden) front end with custom top A-arms. VK Commodore power rack. It's a very "quick" rack on this car. Would an underdrive pulley slow the rack down?
Rog - no I didn't sit in the car and I wouldn't have enjoyed sitting up on the hoist for 3 hrs. I'm sure it makes a difference but I'm not chasing 10ths of seconds, just after a good, stable setup.
Treeve - I might lower the tyre pressures a little to see whether it makes the steering any heavier.
Muzza - looks like I'm off to the bolt bloke on Saturday. I did ask for +6 deg caster so maybe I'll attempt that myself. I have a Longacre camber/caster gauge which I know how to use except I have trouble getting the toe right - relative to the back. Total toe amount is one thing, relative to the centre line is another (for me). Any tips?
Also Muzza, what is the effect of the roll centre being too low?
Here's a photo of the left side. The front lock nut just covers the bolt - maybe 1 thread off. I'll fix that on Saturday.