Apologies for this evening’s slowdown and eventual error messages regarding the inability to connect to the database.
The problem was due to someone who submitted at least 730 requests within 2 minutes for individuals diaries. The address range, and browser type did not indicate this was a normal search engine spider, and given the sheer number of requests from the particular network I can only assume it was intended to be a denial of service attempt.
I have traced the perpetrator and have reported them to their ISP, along with plenty of evidence from the machine.
For those who are interested, the server load hit over 90 briefly until I traced the source and blocked it.