Thanks for the advice on having to actually connect via HTTPS rather than just enabling it. I simply turned off the HTTP option and just left HTTPS and the password fields appeared. So that solved that problem.
Having just tried another test scan though it failed with Error (027-529): Data read failure from SMB server. However i suppose i should start another thread on that.
Why is this so difficult, why can't Xerox just produce a piece of soaftware that connects with the scanner like all the other printer companies?