I believe that the limit on astigmatism was removed for renewals, it is just the 2.00 at the initial. Under the new document issued in December 2006, eyes need to have a comprehensive testing every 5 years.
http://www.caa.co.uk/default.aspx?ca...=90&pageid=534
There is one exception, The document clearly states that if you have astigmatism of 3 or more then you need to be tested every 2 years.
Sagey