My first reaction would be to make sure they know about the problem at the highest level. The attitude of the Service Desk should certainly be reported click here
and you can see what other customers have said about them click here
Seems Daniel is popular with at least one buyer!
I doubt you'll get much joy before Xmas now, but I would find out the e-mail address of the Managing Director and make sure he sees a copy of the e-mail, and also post a copy of this on the ConsumerWatch page.
Oh yes - telephone number is, from click here
020 8965 0090