Ok, lets take your haddock example.
Its a mislabeling of food, without a doubt, for a massively inferior product, BUT [/ B]the original is not readily available in this country and if it is available its horrendously expensive, but there are no religious restrictions on eating the original if one can find it.
In terms of the Halaal thing, its taking a food that is haraam, modifying it into something massively inferior just so that it passes the Halaal test... why not just call it beef sausage pizza or something, what is the appeal of eating a pepperoni pizza when what you are eating is not pepperoni and you can't eat the real thing because it is haraam?