Not sure that I've ever seen a Registered design No. - that was minus the letters Rd., which always precedes the No. as far as I know, and the fact of having a No. would mean it had been Registered by the Board of Trade. Perhaps Fred can shed light on that aspect.
Jenny Thompson's book omits this No., which if it were a genuine British Registration would have been around August 1897, although as we've discovered in the past some Registrations were classified wrongly, and ended up in CLASS IV instead of the correct CLASS III for glass - and as a consequence were missed by researchers like Thompson, Slack and Lattimore.
Perhaps made outside the U.K. and imported?
Other countries used a similar system for registering designs, certainly the States and possibly Germany.
Take it these other pieces you mention - without the Rd. - also came into the shop.