Answer:

Here's a quick guide on setting up your toe after a rough guestimate when assembling the front end.

Starting point: 1.25 degrees negative camber (measured with a camber gauge, i.e. bit of string on a board with a scale on it), castor set 3 washers on the front and 4 on the back (make sure the top wishbone is the right way up or it will never work right )

Symptoms - car does not auto centre going forwards, but it does backwards. Problem is too much toe in. Marlin recommend  the wheels be parallel  - not sure if they are wihout measuring equipment, but it feels good to drive after this procedure.

1) Mark on the track rod a line so you know where the top is.
2) Unbolt and turn the track rod by 1 turn so it move out from the track rod end - this moves the wheels outwards at the front. Do up the nut that locks it in place.
3) Take it for a quick drive forwards and back and see how it feels. Ours felt a bit more neutral going back ward but still no auto centre.
4) Repeat if needed, we did with a 1/2 turn, do up the nut that locks it in place. Now backwards wasn't auto centring much at all and forwards was doing it a bit, but not quite enough.
5) Repeat if need, we did an extra 1/4 turn, do up the nut that locks it in place. Now the auto centring forwards was very good. Still slightly loose around the middle but 1/4 turn and it runs nicely back into line.

This has a made a huge difference to the handling feel. It feels nimbler into the bends and is easier to steer you also relax a bit and use less concentration for the steering.

I've also moved my seat a notch forwards which is less relaxed but gives me better control.