solved
Thanks for helping!
I have double checked the group and browsers, etc. All good there.
I deleted the account and recreated it with the same details. Still didn't work, same problem. So I deleted it again and created a new account this time with different name etc (test user) and it all worked.
So I edited the test user, changed the details back to what they should be for the staff member, and it worked.
Very odd indeed but it's working so that's great.
Cheers
Reuben