Mark,

It looks like a great rifle!

Cartridges of the World, 10th Edition says:
"This round, identical to the 7 x 57mm Mauser, was adopted by John Rigby & Co in 1907 for Rigby bolt action magazine rifles. Rigby was, at that time, the British outlet for Mauser. Rigby's original rifle featured the 175 grain bullet. It its 1924 catalog, Rigby lists three versions of the Mauser, its No. 1 rifle for the 175 grain bullet, and its No. 2 and 3 rifles for the 140 grain bullet, designed for deer stalking. The No. 1 and 2 rifles weighed 7.5 pounds and the No. 3 was built to weigh 6 3/4 pounds."