This is a solid cast brass ‘ring’ plate, with a highly-burnished finish. It’s a variant of the N657/V40 Bridge handle which appears in the 1960s’ Newman Brothers’ catalogue. Dr Julian Litten, expert in English coffin furniture calls them “Art Deco Odeon Cinema Style” fittings.
Newman Brothers produced a select range of high-quality Art Deco handles during this period, all of which were registered with the Board of Trade. They do not appear in any of the surviving Newman Brothers’ catalogues, but we know Newman Brothers made them based on their Registered Design numbers. It seems Newman Brothers did not have new catalogues printed regularly, many of their Registered Designs would have fallen out of fashion before the printing of the next new catalogue. Presumably they couldn’t justify the cost of updating catalogues for a handful of new designs.