Coming back to this after my brief earlier response (someone at the door!) - yes indeed, thank you Paul for taking the trouble to go and check these out for us. I've sent an email to alert Angela to your extra information, I'm sure she will be most interested to see this.
Reading the Nat Arch entry I see it refers to the Patents Designs Copyright and Trademarks (Emergency) Act 1939, which I've looked at before in respect of designs, and I would suspect this indicates that these items were made in a country with which the UK was at war (i.e. Germany or one of the countries under German Occupation). I can't imagine why it would need to be invoked if these were originally made by a British maker. So, I think we need to start searching German, French, Polish and Czech catalogues of the 1930's and 1940's to find the maker... Henry Dresel being the importer, of course.