I received the following this morning;
Dear Jb Webb-Benjamin, (Customer ID: [redacted])
Thank you for contacting us.
We have received correspondence from the Parallels support team in regards to your issue:
"Thank you for contacting Parallels Technical Support.
We have fixed the issue with database error. Now we are able to access http://uknexttopmodel.com/test .Please cross check the same at your end. We have just updated the application settings for wordpress. We have also reset the Administrator's preferences password in the word-press settings. Please cross check the same at your end and let us know if you have any further queries.
I am going to mark this ticket as "resolved". Please, bear in mind that it does not mean that your ticket is closed - there are 14 more days for you to re-open it and ask any questions about the initial issue. We would be glad to follow up on your request.
A feedback form will be sent to you soon. Kindly submit the feedback to help us improve our service.
I do appreciate your cooperation and understanding.
Technical Support Engineer
If you have any further questions please do not hesitate to contact us.
Dedicated Server Support
I tried their test subsite and yes it worked fine - until I reactivated the WordPress Network. All Plesk had done was reset all the passwords :( and remove networking ability from WordPress. As soon as the networking was reinitialised their test subsite (and the new one I created as an additional test) all came back wit the Error establishing a database connection problem.
I just don't know what next. I've reported it for reassessment by Plesk but I'm now considering dumping this dedicated server and getting a different one from a different company - big problem for all the 28 live sites I host though! :(