Site was down from ~4AM Saturday whilst I was performing the upgrade at which point the load went out of control and lost connectivity to the server remotely, the host restarted the server but as soon as it came online processes would spiral out of control again, this happened all the way up until 11PM where the site was moved out of harms way which created another set of issues initially and took many hours to resolve.
Host has confirmed an attack directed at the site and may explain the recent bad run we have had to what has been a rather unchanged site so a case of watch this space.