Thanks so much for your reply 'indesigners', I really appreciate the rapid response!
I've had a play round with the 'fixed boxed position' and this is a great feature, which does exactly what I need! The only part I'm not sure about is the 'z-index'... I've read up on this, online, however I can't get my head around how I would implement anything - do I need to insert specific code in the CSS section to achieve moving this layer to the background? Any help on this part of the issue would again be greatly appreciated! Many thanks in advance.