by John Andrewartha.
Hi Will,
You are almost there, the base URL of the site is http://computingforschools.co.uk/
DNS is fixed but we still have that error message in a lovely bound orange box when we hit http://www.computingforschools.co.uk/ remove the part highlighted in red and all will work as you expect and desire.
Here is the reason http://www.computingforschools.co.uk/ does not exist in the view of the humble Domain Name Server and the server which Moodle is on.
As another Will said " Whats in a name?" In computing a name is everything, it must be the same across every thing that uses it. No additions or typos.
You deserve a reward, I suggest a single malt no ice, and I am sure Ken would be happy to join you.