Someone helped me sort this. I was not aware of this, but if you have
Google toolbars installed then fields available for "auto fill" are set to
yellow overriding the CSS style sheet.
So this question has been resolved. Does raise another question though:
Is there anyway through CSS to override the Google styles when someone has
Google Toolbars in their browser?
Supported by evolt.org -- http://www.evolt.org/help_support_evolt/