full domain or not

Maybe not the right forum to ask this question, but I know we have a few techies in our midst.
Can someone please explain the difference between mybandb.co.uk and www.mybandb.co.uk when it comes to google?
I seem to have both registered with google webmaster tools and some of the stats such as content keywords are very different between the two. Does that matter or am I spreading myself around too thinly causing my position on relevant searches to be lower.

I should know the answer but I've forgotten. My site is/was like that also. I still find iterations of both.
You can tell google they are the same thing in webmaster tools.
Pick one.

You can actually force both into the same domain. If I remember correctly, you make an httpd.conf file or is it .htaccess file using RewriteEngine. Your host should be able to help.

If something is accessible as two different URLs, then search engines will consider them two different pages (unless you use the rel=canonical meta tag) (reference: http://googlewebmastercentral.blogspot.it/2009/02/specify-your-canonical.html)
So you should always avoid having the same content available via different URLs.
Just redirect your non-www domain to the www one, or vice-versa.