Specs in the manual says 7.5*BTDC at idle.
Managed to get it idling at 850-900revs and it idles and revs nicely now.
Couldn't get it to idle any lower than about 2000 revs which turned out to be a tiny weeny piece of fluff in the idle jet.
Watching the advance with a stobe and it advances smoothly when revved. Seems to pull OK and return to an even idle so i'll leave it like that for now and just take a 10mm spanner out with me next time incase i need to do some slight adjustment.