A quick jemmy with a knuckle bar and a couple of pieces of wood and off come the carbs.

The Haynes book of lies says to use a pencil to help compress the spring into the carb top, then hold with your finger and put the cap on. That actually worked first time and both the spring and diaphragm were seated just right. Besides, I've not ridden the bike since I checked that diaphragm.
Now I just need the time to strip, clean and check the carbs.
Alex.