well, fitted a new metering head and it started...just. now it's only firing on 3 cylinders.
got a random crypton tuner coming in the morning....lets see how much good/bad he can do.
EDIT : swapped old metering head back and it works fine now.
missing screw my arse.
the thing thats really pissing me off is that i've used him for years and he's always been cool. he's getting pretty old so maybe he's losing the plot.

I think i'll book into JBS in chesterfield so they can set it up properly on the RR.