Yes, I noticed it was a 'W*' forging. It's reckoned those marks are from different sets of dies used in the drop forging process, they made huge quantities of these spanners over many years and the dies must have become worn and need to be periodically replaced.
They could possibly be date related, but I don't think so.
Other minor detail variations in the castings are consistent with the 'A', 'B','W','*' etc so to me it looks like when they changed the dies the replacements had those marks in them.
There are people who attempt to match up sets all with the same mark, and I have seen some of them advertised as being all 'W' marked or somesuch.. but i was trying not to focus too much on that in an attempt to preserve some shreds of sanity.. I may have to go and look through all mine now, including the duplicates and the sets under the Land Rover seats that's going to be about 150 of them to check..