>but not Chuck? What gives?

Funny isn't it? We just don't ever seem to use that particular abbreviation for Charles. I remember "Dame Edna" interviewing Charlton Heston and making him wear a big hand written badge with "Chuck" written on it, I'd never heard the word used as a name.

It may be that in the North of England (Coronation Street country), everyone is called "chuck",like "luv" it is just an everyday term of endearment. In the Midlands, particularly around Nottingham the word would be "duck". In the North East it would be "hen".