... In other words all the date tells you is about the registration process and not the date the design was introduced.
What a misleading comment.
It is obvious from the context that we are discussing British designs (or plagiarised American designs like the Grace Darling boat, which are effectively the same), manufactured and registered in Britain to protect them in the home market. We are not discussing international protection, international manufacture, nor are we considering oddities like Davidson's reregistration of old patterns to keep them protected indefinitely. We knew of just one example of a lengthy time period (just over a decade) between design and registration in this context up to February 2008, when Sid, with help from James, Roy and myself showed that it was a previously unrecognised error by Simon Cottle in his book on Sowerby, incidentally demonstrating the importance of this message board in providing an international forum. As far as I am aware no other examples are known.
As a mathematician and statistician I am 99.9% confident that in this context designs were registered as part of the development process â€” that there was no significant delay between design and registration. This is as close to certainty as you are ever likely to get with the imprecise world of history. There are scenarios where a delay would have been reasonable, such as seasonal goods, event souvenirs, and a forthcoming trade catalogue, where you would expect a delay in registration so as not to acquaint competitors with new designs until the last possible moment, but even in such circumstances I have not found examples.
I hope examples will emerge. It will be interesting to examine them and consider possible explanations and their implications. However, a handful of exceptions will have no effect on the generally established rule, that, in this wholly British context, there is a strong, significant, and tight correlation between the dates of design and registration.