Sidebar Disappeared

Hi
I can’t get the right sidebar to display on any of my pages. I’ve checked the templates index.php and single.php have the php include sidebar code in ‘<?php get_sidebar(); ?>’

I’ve made sure I have at least one post (although I don’t want any eventually).

The only file I’ve edited is site.css to change some colours from black to purple. I’m using the Twenty Eleven theme.

http://www.suffolkcruse.co.uk/about (the site isn’t ‘live’ yet and there is a standard HTML web site on that domain. I’m waiting until the WordPress site has been tested before making it ‘live’)

Please can anyone pinpoint the source of this problem for me – I’m a relatively new WordPress user and I have 3 sites using WordPress.

Marian