Yes, I see that they have made some changes - thanks for letting us know via this forum, as no one has update me from virginmedia!
As you say, can now see what accounts exist but can can only delete, not manage from that page.
I also see elsewhere on the web-site it tells us;
"Please note, Virgin Media no longer offers the ability for customers to create new Virgin Media email addresses. Customers with an existing Virgin Media email address will not be affected; their mail account will remain as is."
The only problem is, there does not appear to be a way to find out what email addresses actually do already exist associated with this primary account. Possibly there is a convoluted way to do it by logging in to each 'associated' account separately, but very inconvenient if you are trying to manage a family's mailboxes from the main account....
Definitely big steps backwards for the usability and convenience of this service provider.