I see you've had no replies, possibly because of your request for the 'definitive' source....I'm not sure there is one, its so hotly debated. I tried a google search on ANODES DUFF MG BOATS but there's more there than I want to read.
Interestingly a seach on AOLs own engine came up with practically nothing, even though its supposed to search the others.
Alternatively contact MG Duff themselves at Chichester Marina who are supposed to be the absolute experts.