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Age, yes - the arteries have to harden sufficiently and the blood pressure climb high enough.
Class - I don't really see that, I think the port and stilton diet is probably the optimal choice for a nice rosy complexion to be attained.
I think those trying to suggest that Gammon is aimed at the white working class are acting in bad faith here - it's the same thing as Mogg calling those seeking to frustrate Brexit "the elite".
There's probably age and class coded in gammon too, but less precisely than race and gender.