When the Facebook scraper looks at my page it closes the head tag when it finds a noscript tag. If you view the page source you will see that the meta tags are within the head tag of the page. Look at the debugger for the error: http://developers.facebook.com/tools/debug/og/object?q=http%3A%2F%2Fwww.rightmove.co.uk%2Fproperty-for-sale%2Fproperty-34534103.html
On the Facebook open graph debugger you get a different page that has closed the head tag early: http://developers.facebook.com/tools/debug/og/echo?q=http%3A%2F%2Fwww.rightmove.co.uk%2Fproperty-for-sale%2Fproperty-34534103.html
Strange ehy?