If the linkage between my case's hallmark and the razor's serial number can be trusted, then I would think that pulls that whole series a bit later than you might like, George. Sure, there'd be some gap between the two, but I would think that it would be closer to 1910 than 1908.
Good to see you back. So....you've been holding out on us.
I have to admit that I'm struggling a little with your logic here. It would seem to me that the simplest explanation is that the Sterling cases would have been supplied as an after market item by some enterprising silversmiths. Hence the Double Ring in a 1914 hallmarked box.
Your single ring is the earliest E series found so far. As an aside, I've often wondered what the starting number for series might have been. Has anyone sighted a razor with an alphanumeric followed by five blanks or zeroes and a 1, or did they start numbering at 100 (I have H000882)? Whatever, E078912 is early and the consensus seems to be that there was an opening of a factory at Leicester in Jan 1909 so I would have thought that, on that theory alone, your razor would date to shortly after that. However, drawing on my business experience, I can not get comfortable with the possibility that, having acquired a lease on what Marshall described as one of the best factories in the district and shipped in the machinery by mid 1908, KCG would have countenanced the facility sitting idle for 6 months while orders piled up. I think that the entirely reasonable explanation is that the lease was for the purpose of allowing production to proceed while the purchase option was taken up and the new or extended premises were built. I think that when the new buildings opened the new owners (The English Company) took the opportunity to stamp their authority on new production with a new marking protocol. Such a re-jigging would not be a trivial or cheap exercise and I can think of no other commercially sound reason why they should have done so.
Interesting suggestion by Adam regarding the ABC razors. My feeling is that ABC would have supplied the handles at least, and while the heads that are marked with the diamond with a horizontal line may possibly have been made in Britain, I think it unlikely as one would think that they would have used the British serial numbers. What do you think Porter?