Apologies everybody for the recent site availability issues.
First off the webhosting company forced an operating system change on the site that broke it, while investigating that they changed some other settings which had no impact at the time.
Once it was realised the issue was due to the operating system change the hosting company undid that change which restored service.
A day later they undid the other changes they had made, however in undoing the other changes someone fat fingered a number and missed out a digit, causing there to not be enough memory allocated for the site software to run.
Du-Oh!
