I'm afraid I come to this discussion a little late, but thought I'd confirm one or two things.
The bubbled pieces have been mistaken as Whitefriars for as long as I've been collecting (40+ years). They are (as Has been said) S&W/RB, and, as far as I know, were made in the 30's and into the 50's. This means that they pre-date both Caithness and Dartington - so the label has definitely been fixed on by someone after leaving the factory.
I sure most (if not all) of you know that Dartington now own the Royal Brierley name, but just in case it's worth a mention - if only as a bit of irony!
The bubbled pieces that are ginger jars have been around from time to time since I started dealing back in June 1986; they always look as if the lid is an ash tray turned into a new use. I'm sure I have a threaded version in the store somewhere - I seem to recall that they have a much better 'fit'.
Cheers, Nigel