I am English and I have heard this expression before. It's quite old fashioned, and you wouldn't hear 'city/rich' younger people saying it, but more 'country/rural' people may well use it.
The expression apparently was made popular by an American political campaign which used it as a catchphrase: it referred to butchers at the time (1820s) asking customers if they wanted 'the whole hog' or just part of the pig.