I wish a Record catalogue from the 1920s/30s would show up (I wonder what other weird and wonderful versions they experimented with?)
[/QUOTE]
In this period and somewhat later, their brothers (literally) at Woden probably had more variants of the QR woodworking vice, as did Rededa (well one more type) over the road (more or less), and Vono (closer to the old Hampton home near Brum) had another. Then all reverted to the original model based on Parkinson, but with twin bars, not cast/machined slides.
And why did they all choose the same sizes: 7in, 9in and 10.5in (with a 6in light version)?
There weren't many English metal woodworking vices before Parkinson in 1880s, but they mostly had jaw widths of 8 to 11ins (and a very heavy build).