I don't think the barrel work is WR original. The Caliber markings are not British., .45, 2.1 being distinctly American Also British rifles will bear proof marks and the companies name on the barrel, especially if it's Westley Richard. Besides WR had their own full set of properietary cartridges, most superior to the 45/70, which is also an American cartridge.
Doesn't realy mean anything as this rifle is beautiful. I have a similar action, marked I.Hollis that I am going to build in .450 Musket No. 2.