Welcome to our Community and thanks so much for your first post. When you leave our family, email addresses are usually deleted within around 90 days. Sometimes if they are in constant use, they can miss the sweep and remain connected.
If you are still an active customer with us, the email will remain if it's the primary email address. This cannot be deleted. If it's a secondary email address, you can delete this from your online account
The blueyonder addresses haven't been in use for over a decade although one still appears to be shown as my Virgin Media Mail address. Surely there must be a workaround here other than cancelling my Virgin account and starting again.