I think there is a very good chance that the gouge was made by W&B (razors) as you say the proof marks are similar.

I have a dovetail saw with the makers name W Tyzack Sons & Turner Sheffield England on the brass back, the blade is etched with their marque which was 'silver steel tested for hardness Non Pareil' in scrolls either side of an elephant inside a shield.

A young Henry Tyzack moved from Sheffield to Shoreditch East London in 1839, and began selling saws, perhaps the move may have been to act as London merchant for the saw business of Henry's uncle, Thomas Tyzack. He also had an uncle William who set up his Sheffield tool business as early as 1812.

Much of Sheffield's output was exported and most was done through London merchants so It is likely that Henry came to London originally, as the marketing arm of the family businesses.

A branch of the Tyzack family (headed by Walter Tyzack) in Sheffield, joined forces with one Needhams Ltd and a James Veall in 1879 to form Needham Veall & Tyzack Ltd who operated their business from the Taylors Eye Witness Cutlery Works.

I think it's safe to assume that many Sheffield tool makers and cutlers were interconnected, after all they share the same production requirements and similar tooling, forges, and machinery, it makes sense that these factories would have diversified into other products to maximise profit.