The server that this site is hosted on has undergone a series of attacks over the past few days. These have ranged from attempts to insert malicious code to attacks that have dominated the server processor time leading to there being no time to process requests from the site.
Additional security software has been installed, but I may still need to take the site offline for a while to carry out additional security scans and modifications. I will endeavour to do this at times that cause little disruption, however there will be some disruption so please be patient if you cannot access the site.