The ginger pig (the place I was talking about in the previous post, presumably you worked that out) was just an example. I've found the same outside London (and internationally). The reality is your average butcher is going to be getting their meat form a local abattoir, probably the same one the regional supermarkets are getting their's from. They don't have the overheads, but they also don't have the buying power or scale.
While I don't disagree that the meat from the GP is likely to be different than a supermarket (most of the pork at least is from their own farms, with different breeds) taking it as gospel from someone that works somewhere that "their product is better" is a little naive.