Stripped the carbs down for a good clean up and refurbishment. I have four carb service kits ready to go but thought it would be a waste to fit them to the dirty carbs.
Stripping down was easy, apart from one of the water connections into the carb body. The brass fitting had actually sheared and was only held in with a "limescale like" substance.
Time to either hunt for this obscure connector or junk the carb heating circuit completely (and see if it will suffer from carb icing as they are supposedly prone to do)
I shall do a little research and come up with a plan!
Next is to degrease and clean the bodies and carefully clean and reassemble them.