As mentioned, I don't have a Mathieson catalogue with this rounder in, but I have just found this image of a dowel rounder which I think might be the same thing.
The image is far from clear, as it comes from a photocopy, but the shape is similar, there's a line on the end which could be the cutter and there's a retaining screw in the right place.
It's from the 1891 catalogue of Charles Nurse and son, who were a big London toolmaker, wholesaler and retailer.
The engraving shows it marked "C N & Co" ie Charles Nurse, rather than Mathieson, but such "OEM" marking was commonplace, on the actual tools and on the printing blocks used to illustrate catalogues.
What may help a little with the dating is the fact that this pattern of rounder does not feature in the 1902 or 1908 catalogues from Charles Nurse.
Instead, by 1902 you could buy the more common pattern that looks like a big conical pencil sharpener, for only a shilling. The Mathieson style rounder was
very expensive, which would help explain how rare it is!
Digitalbot, your challenge, should you wish to accept it, is to find the other size. :lol: