Question Author
OK, many thanks, TheWinner.
When I posted my question, I didn't see it as necessary to explain that I often use the extensive box of symbols when I'm composing e-mails, writing reviews or making notes for my draft folders, to lift things like accented letters, fractions, or any other non-standard letter forms that aren't available on an ordinary keyboard. It had occurred to me more recently to see if there was a barred 7 in that box, as it seemed reasonable that with it being a widely used form, it should be there - but it wasn't.
That is virtually all I ever use MSW for.