[Adam H]

You can try using something like this :

https://vborg.vbsupport.ru/showthread.php?t=225080

I have no idea if it works the way it should as ive never used it but cant see a reason why it shouldnt.

Obviously redirects are your friend in a situation like this so you should be redirecting your non www. to your www or visa versa , your index.php to the root folder and going through your webmaster tools ensuring there are no 404's which should be redirected.

There are loads you can do to a vbulletin 3 template to make it more seo friendly too like adding relevant h1 and h2 tags through out the site, remember not to make any h1 tags site wide like some people seem to like to doing with their logo.

Using conditionals to remove unwanted bloat for guests and reasserting your content to code ratio is something you can look at.

Another thing is to increase the speed of pages, including CSS sprites , optimising images and general overhaul of on page aspects to make your site more streamline.

Other things you really need to learn how to use properly is the robots.txt file, Blocking the pages /folders/ files which do not really need to be indexed.

Even with out a vbseo licence you can still use the VBSEO sitemap generator , set that up so it doesnt include the post pages and just has the thread pages.