some more information from the Kew Archives, but don't think the name of Henry Dresel Ltd., is going to tell us what we really wanted to know - which is details of the maker.
Despite the written description stating that this was a British company, the name Dresel sounds possibly more Continental in origin, and they may well have been agents/wholesalers/importers only, but with connections to small manufacturers in Czechoslovakia, Germany etc.
Presume this must have been a reasonably successful design as there appear to have been two five year extensions for the Registration, ending finally in 1965.
Hope of interest.