I have been faffing about and managed to update the software that runs this website. SIte was moved from Mambo 4.5.1 to Joomla 1.0.5. Didn't go too badly considering. I'd moved this site to the main shared server at my work a while ago. It's now running on apache2 (2.0.54),  php5 (5.1.1) with MySQL 4.1 (4.1.11)