Lovely pen Paul, I have some of the same and it's one of the better patterns imo.
Just to clarify though, Vince sells 2 distinctly different types. the one you have isn't the Conway Stewart material he sells which is supplied as solid blanks. The others like yours aren't drilled out from solid, they're actually acetate vintage pen tubes. If you look closely you can see the join lines of the windings. It is beautiful material but you need to be careful with it if you drill it out not to twist back the drill in reverse as it is possible to "unwind" the tube. Don't ask how I know
. It can be glued back with CA though.
These tubes were used by a number of famous pen makers, probably Conway Stewart as well!