Hi Stewrog1982, welcome back to the community! It is lovely to hear you have returned to us as your provider.
Sorry to hear of your difficulties getting registered for My Virgin Media with your new account. There are several reasons this could be happening:
1) As your services are not yet activated the My VM account has not clicked over on our systems to being active which is preventing your access. I know you mentioned you are due to complete installation today (7th April) - it would be good to know if you are able to access My VM once your services are active! It is worth trying a password reset through the 'forgotten password' option when trying to log in if you still have difficulties.
2) The email address you were trying to register/log-in to My VM with is still associated with your old account and not the new one. We will need to raise an IT ticket for you internally to ensure your email addresses are provisioned correctly across old and new accounts. In order to do this we will need to send you a PM to confirm some details (including your email addresses) to be sure we have your account provisioned correctly.
I will send you a PM to confirm these details so we can ensure this gets resolved for you as quickly as possible. We will return to the public thread with an update as soon as possible!
All the best.
Molly