Once again I am being lazy. Does someone have either a function or an
elegant approach to take a text string and randomise it (to create a
password for WinZip in this instance)?

One way is

(a) put the letters A-Z in A1:A26 (or your favorite characters)

(b) put =RAND() in B1:B26

(c) sort A:B by column B

(d) take the A1:A9 values as a 9-letter pasword (or more or fewer)

Not elegant and not function, but I find it fast and easy.