I really hope this is true and not wikipedia vandalisation:

"The name "Fieldy" is said to have come about as an abbreviation for "Garfield", based on the comic strip character of the same name. Originally, his band mates called him "Gopher", due to his large cheeks. Gopher became "Gar", Gar became Garfield, which became Fieldy. His full moniker is "Fieldy Snuts", which when spoken aloud sounds like "Feel these nuts", or "Fieldy's nuts". This is also the name of his record label."