If you are referring to the iphone/ipad link, it is not about changing the password. It explains that the iphone software retains the wrong smtp server settings even though you think you have deleted it. You need to double-delete the outgoing server after deleting the address(account) from the email client. Then the fresh set-up will have just one outgoing server and should work. (cross fingers)
Are you still showing as listed on the SBL? If so what else does it say?
Ignore the PBL listing - your home IP should be on this.
@MissPasko - Just something for you to think about going forward.
If they are on the CSS then the error message will end up having the same effect as if they are using a wrong password, even though the underlying error is one of the 525 authentication denied errors. Thus if they say they're on the SBL - check if they're on the CSS and take it from there. If they are then there's no point in getting them to change the password until the CSS listing has cleared.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.