Sorry about that!
The 4 hours of downtime was caused because an optimisation process was run on the database, by my request, by the server company.
There was an issue with one of the tables during this optimisation process that wasn't caught by the server company, and I was away from the computer at the time this took place. Once I got back and investigated the issue, I found the problem and got the site kicked back into action.
There was zero data loss as the error was on a table that is used for some simple background log info.
There are a few little bits to tidy up from this issue which will be done in the early hours of the morning to minimise disruption.
Once again, I'm sorry for the inconvenience caused by this downtime.
James