As per my post of October 15th:
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 (although Don Varnau explained a bit in one of his replies), nor why this issue suddenly arose on 9th October. Whatever it was, the error (wording as set out in my initial post) was instantaneous and repeated each time WLM tried to send & receive. This happened instantly and continuously for over 2 days until I cleared the dns cache (Elevated command prompt, ipconfig /flushdns) and registered the dns (Elevated command prompt, ipconfig/registerdns).
This is one article I found helpful https://sourcedaddy.com/networking/registering-and-flushing-dns.html
I am again having intermittent problems. I am again getting the "Unable to send or receive messages for the Live.co.uk (username) account. Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems or a long period of inactivity. Server: 'pop3.live.com' Windows Live Mail Error ID: 0x800CCC0F Protocol: POP3 Port: 995 Secure(SSL): Yes" but this time it is not every single time continuously for days on end. It is about 75% of the time. I close and reopen WLM 2012 several times and eventually it connects. It is extremely irritating particularly as I use this email account to pick up replies to this post. It is happening at the moment (ie live.co.uk will not pick up in WLM 2012). It is worse if I am using internet for another purpose at same time as WLM is trying to pick up emails. I wonder whether there is some kind of server issue. Are you also live.co.uk ?