I'm thinking it's actually French, or a Belgian copy of a French revolver, and not a copy of a British revolver.
It doesn't have a top strap and, other than Colt, the French were about the only other makers who thought that a top strap was unnecessary on a revolver, primarily because they were, by far, the biggest adherents of the pinfire design, and it's very tough (but not impossible) to make a pinfire revolver with a topstrap.
Also, judging by the shape of the hammer and trigger, and the general location of the screws, it uses the Chamelot-Delvigne lockwork design, which the British pretty much never used, but which was used heavily in Continental Europe.