After hours of searching the forums, I managed to get the answer to the above question.
On my page.php file I edited the <?php get_sidebar(); ?> to:
<?php if (!is_page('forum')) : get_sidebar(); endif; ?>
As you can see, the page I didn't want the side bar on is the Forum page.
This worked a treat. However I was then left with a huge blank space where the sidebar use to be (a problem that occurred for most people). To get around this I added the following to my page.php file:
<div class="<?php if (!is_page(forum)) : ?>content<?php else : ?>nosidebar<?php endif; ?>">
And created the nosidebar attribute in my style.css sheet.
This has worked fantastically. The home page has the side bar, the forum doesn't and is correctly scaled across the entire page.
When I click on any other page other than home or forum, the side bar is centered and under all the content. Why is this...?
Please let me know if you need anymore information or code.
Thank you in advance!