I agree, the museum picture must surely show the holder inverted - this way up there doesn't appear to be any recess in which to stick the candle, judging by what I can see.
As a matter of course, I don't have pix of Registrations post the lozenge period - though I have a few, but regrettably not this one so unable to help presently Lindsey with 114044. I need to visit Kew for a variety of Registration information, but life is conspiring against me at the moment, but I will get there soon and will check on this one for you.
If you have Sheilagh Murray's 'The Peacock And The Lions' - p. 42 - there are three 'candle ornaments' shown - a shape and design that perhaps we might call drip trays. All three are shown with some sort of design ornamentation around the perimeter 'that sticks up'. Murray's ornaments are in a style similar to the V.&A. - except that the museum has the ornamentation pointing downward - so seems little doubt that Murray is correct and the taxpayer funded museum are wrong.
Didn't expect you to find a large piece of Sowerby so quickly - is there some outside chance you have used the wrong ruler?
I often see those Bagley and Davison black circular plinths - for bowls and other flower containers - in charity shops placed upside down - perhaps they imagine they're ashtrays or bowls of some sort.