As you can (hopefully) see the instant preview is wrong on google search. It seems to ignore most/all of the css. Whereas in the testing tool in Webmaster Tools it all looks fine. I have also fetched as googlebot which is fine, I have checked robots and individually requested the css files as googlebot, and the site has no crawl errors. Also strangely, sub pages that have been indexed appear fine in the search list - it is only the home page that has the issue.
Any light that you can shine on this would be greatly appreciated.