I have now finished updating the code on almost all sections of my website. My main, family and blog sites are compliant HTML and CSS. My picture gallery is compliant HTML, but not CSS due to some vendor extensions in the style sheet.
The point of doing this, is so that the pages should display cleanly in any browser that it is being used. It has also made me look at the layout of the pages to ensure they are clear.
I have taken the opportunity to update the keywords within the pages that the search engines use. The addition of my UK site, www.ijhedges.co.uk, has had the desired effect, my pages now also appear in the google.co.uk search pages.