Many thanks for your replies, cocospm & manicguitarist. They are most helpful, much appreciated. I may have to avail you of your help again when I come to get this installed, hope you don't mind (new to the game, I'm afraid) .

No problem at all!

Update: I managed to set up a guest network using an Edimax BR-6574N using basically the suggestion in this thread. It was dead easy. Thanks for you help everyone.