As far as I am aware (and I'm not technical) my research indicated the problem was in the dns. I cleared the dns cache and registered the dns. This seems to have worked and I am currently able to pick up pop3.live.com in WLM. Why only my live.co.uk email was affected and not my other POP3 email accounts (gmail, btinternet & AOL) I don't know (perhaps you do?), nor why this issue suddenly arose this week.
Perhaps you, as a Moderator, can explain why this happened and why it only affected my live.co.uk email and no other POP3 email address on WLM 2012 nor any other internet service. Is this likely to happen again?
Glad that you thought to clear the DNS Cache. Random problems with the DNS Cache just happen. You didn't do anything to cause it and you can't prevent it.
If it happens again, clear the DNS Cache again.
Don