Having a few problems with the footer and can't work out what's going wrong.

Our site is a fixed width 960px and everything is fine. However, I want to extend the footer the full width of the screen so in Template Editor>Site I set to Fixed Width, 100% Footer.

As soon as I do this, the header on the home page only, shows a 4 pixel white gap either side. This happens on the home page only and doesn't show on any other pages.

The strange thing is, when I 'inspect element' in Google Chrome, it shows up with "iframe name="oauth2relay489823160" 4 px x 4 px" around the header. I'm not sure if this is anything to do with the problem or if it is a padding or slider problem.

Grateful for any help on this.

Website is at portalvitality.co.uk (I've got it back to fixed with at the moment so the gap is not showing)