Many thanks for this,
I suspected that I may have gone about my customer database a little bit simplistically!
There are actually three entry validation fields in the database, one for username, one for password the other, a concatenated field that I am currently doing the "find" on.
I thought I could do more-or-less what you have suggested on the concatenated field, but you are hinting that a relationship would achieve the "exact" match that a simple "find" can't do properly?
I'll have a try at the relations approach.
Thanks again