Gosh! Those are nice, Rob!

Just the sort of thing I like .... and what no-one here seems able to help me with!
I'm sure I've seen something like them before, but I can't remember where. I know Thomas Webb did some acid etched designs, but the only ones shown on the 'Replacements' website are WET49 and WET50 I think, which these aren't.
I have a feeling you may find it difficult to identify these!