OK; the carb is wrapped up and will be on its back to Mr. Williams tomorrow.
To highlight a few things during the rebuild process;
First and foremost, the carb was suffering from a pretty bad case of fuel contamination. The filter on the left is the one out of the rear bowl on Toms carb, the one on the right is a new unit for comparisons sake.
Yes, it is essentially plugged solid. The insides of the float bowl looked even worse.