yes, I also understand that there has been some re-assessment of Manley's attributions, although I have to admit total ignorance about this sort of decorative Victorian glass, so make no comment myself - as so often, my information comes from books.
I believe that for some of his material, Manley had first hand knowledge, or had spoken to workers who remembered the manufacturing details etc. - although in this particular matter he doesn't explain exactly why he was so convinced that weak blue and opal was a Boulton & Mills feature.
Must admit that my thoughts on 'ground and bevelled rims being Continental' are tenuous to say the least, and are based on some information from somewhere where it was stated that this type of rim finish - on drinking glasses - was likely to be Continental.
You're quite right, of course, that rims with this finish can equally be British - see Gulliver - who, under the heading of Component Designs/Designs for Rims, includes ..........
Ground off, and polished.