Well, interestingly, I've undone the changes we made previously and we're going to re-open the bug report.
Reason being that iOS 15 is on its way and for the first time in as long as I can remember they’re actually redesigning the appearance <select> element.
They no longer centre align the text. But arguably the new problem here is the list is too narrow.
So we’re going to watch and wait and see if this makes a difference and if so then we’d probably prefer to keep spaces here rather than dashes.
I've reflected on this a bit more and I think given that we were trying to workaround a sub-optimal approach in a single browser and that sub-optimal approach is being rectified in a future release, I don't think we should make any changes here.