I had a predominantly Middleton terrier a few years back. Bought him up in my native North East and he did have a dash of another line in there. He was a diggable dog, stayed but he was hard. He was aggressive to other dogs and aggressive to his quarry. He was found out when he met foxes that could dish it out though, although he never came off. He had no real class and was killed to ground when he met a particularly boisterous fox in a big earth one day. Dug to him 3 foot down through roots and he was stone dead and not even in a stop end. Not for me I'm afraid.