Thank for the reply guys.
I think it's a bit daft that the only way NTL are letting customers know about this opt out thing is via their NTL World email accounts. If it wasn't for my mate letting me know about the email he had received, I would be none the wiser as I NEVER check my NTL email account. I bet there are a few others in the same boat too.
Are there going to be any plans to send a letter out to customers as well as this email?
As for the caps, as far as I'm aware, at the moment there was no limit on 300k users but once everyone is upgraded, the 30gb limits will be imposed.
Again, thanks for the replies, I feel slightly better now, will just have to keep waiting!