Tried getting the bugger out today and the tunnel the plunger goes in was full of corrosion, gonna use another carb body so end of problem. I anticipated the need for a new choke plunger so bought one (ouch!) it's the type with a spike on it so not sure if it will work on a set standard UK carbs (the bikes a standard 1JK nip import).
The pipe is the only non-standard feature, carbs (now UK), motor air filter are all bog stock standard.