I apologise, I've asked this question on another thread but thought it probably needed it's own thread

I'm trying to find a recorded start date for the production of Stevens and Williams Alabaster range. I've seen a quote from Jackson for 1914 and in The Crystal Years there is a reference to this date, but it does not state that was the date production was started (page 24). So for example in The Crystal Years it has some preamble about the company in the lead up to talking about Alabaster then goes straight on to say ' During the 1914 alabaster period, several colours - blue ... were all made.' That is the first mention of date. It does not read to me that the production of Alabaster started in 1914. It reads to me as though he wasn't entirely sure about the actual start date of the production of Alabaster
I have now attached a photograph of a piece I have with this mark on.
Does anyone know what the timeline is for Stevens and Williams using this mark please?
'S- Fleur-de-lis - W' with England written underneath.
In Charles Hajdamach's British Glass 1800-1914 the mark is shown and the caption reads
'Faint acid etched mark with the fleur-de-lis between the initials S W on a slender green alabaster vase with white alabaster foot, late 19th century, in the Broadfield House Collections.'
Firstly the mark he shows also has the word ENGLAND underneath it although that's not mentioned.
Secondly, I'm thinking late 19th might be a bit early? or is it?
In Cyril Manley's book Decorative Victorian Glass (1988) he shows registered Trademarks and dates and this one (the one shown in CH British Glass and the one shown on the bottom of my vase) is shown as registered
'21 July 1902
reg number 247,653
Stevens & Williams
Brierley Hill Glass Works
Decorative art-glass manufacturers'
Manley says at the beginning of that chapter on Trade Marks 'In some cases a trademark was used as long as 15 years before being registered, ...'
thanks
m