In reply to bentley's biceps:
The Wainwrights are a strange list in that they're an adaption of a personal guidebook selection, and Pedro's point about AW himself not having been up the Howitzer is relevant in that the tradition - insofar as I understand it - is that to complete a round you don't have to climb the Howitzer, just get to the general top of Helm Crag. I know several serious Wainwright baggers including people with 14 and (I think) 19 rounds, and they don't feel obliged to go up the rocks every time. So on that basis, taking the dog to the foot of the rocks is probably enough. Getting a large dog such as a lab up the thing might be quite awkward anyway, as there's a sort of blind back-step corner on descent, at least the way I did it.
Incidentally, re the link to Anne Butler's dog, it did very well to get round all the Corbetts, but it wasn't the first to do so, by quite a long chalk.