Just fired up the Rossa for the first time in a while. Did have the carb apart recently but when the car fires up it seem to chuck more fuel out of the middle pipe of the carb than is going into the car. Must have put almost 2 litres out of the carb in th e small amount of time the car was running <1 min. The float chamber needle does seem to seal ok as I tested it afterwards by holding up the float and blowing into the fuel inlet. Any tips?

Fixed. Rebuilt the carb properly, thank you Haynes!