Tom your Barraud & Lunds is indeed a fine watch with some interesting features.
I think there is more to the supplier of the movement. It was supplied by Joseph Preston & Sons according to Jagger's Supplement, viz. 4595/4624 - 25 '3 keyless fusee movts to own calipers' (p.267)- based on a manuscript in the Guildhall Library. Most of the movements supplied were for their half-chronometer highest quality free-sprung levers. The same source shows a gap in the identified Usher & Cole supplied movements between 4500 (1885~) and 4854 (1926~). Do you have a reference that confirms that Usher & Cole were involved in the manufacture of the watch. On the basis of Jagger, I would have thought a Preston movement, Bonniksen escapement finished by Barraud & Lunds, was more likely. It would be interesting to know whether Preston's stamp is on the top face of the pillar plate - the presence isn't noted by Jagger.
As to the date of the movement, again referring to Jagger, I think it was likely made in or before 1900. This corresponding to the earlier hallmark of 1899/1900 on the hinged dome. Given the difference with the date of the back, and the same maker's mark of John Walton, begs the question whether the original outer case was damaged and the watch returned to Walton to make a replacement.
John