Sidebar appears at bottom

I’ve seen numerous posts and pages where people have their side-bar appearing at the bottom of a page. I’ve spent many hours now trying out loads of suggestions without any luck.

The side-bar is appearing on the bottom of every blog post and not just on a single page, so I don’t think it relates to anything in the post itself.

I’ve tried creating a simple post with only the words ‘I am a test’ and the problem still occurs.

I’ve tried to review all my widgets and can’t find anything that has any dodgy looking html tags but maybe I’m missing something.

I also tried removing every single widget and the problem still occurred, which would indicate that maybe something has screwed up with the css, but I’m guessing now.

I would be hugely grateful for any advice or if someone could take a look. Two problem pages are as follows:-

Thanks in advance.