Ok, this is going to be a potentially complex situation to resolve. I suspect that at some point in the past your primary username has been changed from the Ntlworld email to a different one.
If this is the case changing the password for your current username should also change the password for the Ntlworld email address.
Best now to leave it to the VM Forum Team. I have already escalated this thread to them.
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GrahamI'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media, I'm a VM customer. There are no guarantees that my advice will work. Learn more
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