Use of text on this site
Most navigation elements are plain text and we have provided text alternatives to graphics on the site.
The site has been tested in version 5 browsers and above for Windows, Linux, and Mac and a number of earlier ones. If you find this site difficult to use with your browser please let us know.
PDF file readers
Long documents are best printed using the Adobe Acrobat (PDF) format which is available on the title page of key documents. Please choose a PDF reader for your computer,
Large files and collections of smaller files that have been zipped to provide a quicker download can be decompressed with an unzip utility