I can find several tabs by Henry Senior, but I don't think that's the same guy. It's a pity if he tinkered with the ZB, many people think they need the rods to be parallel when they can, in fact, look quite skewed. Trying to straighten the ironmongery can actually jam them up. They look like they were made on a workmate with hacksaw and files, so there's very little that can go wrong and you can't fix it easily - even by making a new part!
