well what a fun morning i have had..
Started off by cleaning the throttle body.. no better as it has already been bored out and is very clean inside... (did wonder if it was not idling because too much material had been taken off)
then i decided that because it was tapping like hell, i would pull off the rocker cover and have a look, so off came the inlet, etc etc.. checked the plugs and theres tonnes of oil down the bores.. so i think there might be an issue with the rocker cover gasket...
anyhows, threw it all back together.. it idles, rather irratically, first off it wants to die, then after about 10 secs picks up and idles ok.. a bit hunty but ok..
So then i checked out the ISV, Whipped that off, gave it a good clean with some carb cleaning after letting it soak in petrol.. no difference.. I tried unplugging the ISV and it doesnt seem to change the idle at all... it doesnt seem to buzz or feel noisy either.. so i think this might be the next thing to check...