Biturbo, not sure if you've sorted this. I wasn't actually registered for this one but I'm on their mailing list from previous auctions.
Over the weekend I got an the email from the DVLA saying
'there are some registrations remaining unsold. We are offering you the opportunity to buy any of these Unsold Lots at their reserve prices* for a very limited time only.'
I believe you can still register. However, if you need me to check if the plate you wanted is still available I have the list of unsold plates on my email.