Well I never, not one but two of them! Both W4 & W53 have been through my hands, albeit some years ago. I bought a total of nine incomplete No8's between 1997 & 2003 from two seperate sources. I bought them as a long term restoration project, though eventually decided I was never going to get round to rebuilding most of them within a reasonable time period, so sold eight of the nine to a pair of dealers from the Kent/E Sussex area who specialise in Enfield Riflesicon & who are well known on this forum. They completed & sold them on, at least to the best of my knowledge. The one which did not go to them was W53 as I did complete that one & sell it to a pal in my club. He subsequently stopped shooting about 5 years ago after a heart attack & gave me all of his rifles (including W53) to sell on. It went to a dealer in the Warwick area, very close to the Wedgenock National Black Powder Centre.

I'm afraid this doesn't shed any light on where the W prefix comes from, but it surprised me if nothing else!