Argh see this is exactly the two thoughts I've had in regards to this problem so far.
Sidnne6, yes that is why up until now it hasn't really bothered me at all because I knew his actions were that of a total afc, so I normally just laughed when she told me of his drunken calls and then moved onto talking about something else. My main issue is if I don't do anything then maybe his calls will become more frequent and she'll become used to having him as some part of her life again and then perhaps some of the old feelings will start to redevelop. If I don't do anything I'm not sure how long it'll take till he stops calling and gives it up, if ever?!
Stand up, I also see where you're coming from, getting in there and preventing anything from growing could be the best option but the main issue here is creating that 'forbidden fruit' for her by restricting her from talking to him. I'm afraid it would make talking to him more tempting and this could lead to her lying about talking to him, and making communicating with him more exciting. And I don't want to seem insecure because even if I tell her calmly and confidently I want her to stop talking to him it is still an act out of insecurity isn't it?
I have told her when she asked if I was a jealous type, that I don't really get jealous as I am confident in our relationship and thus have no reason to get jealous. She said that she likes guys who get a bit jealous, so far I've shown pretty much no jealousy in our relationship as I see that as insecurity. Perhaps now would be the time to show a bit of jealousy and put a stop to her communications with this guy? I'm really not sure...
The fact that they're friends on facebook again bothers me so much as I believe that once you're over someone you just don't really care what they're doing and thus wouldn't have interest in being their facebook friend, although on the other hand she's very friendly with everyone and tries to be everyone's friend.
This guys is quite popular in his circle from what I've heard from other people (not her) so perhaps him constantly chasing her is more effective cause he's a high status male (socially anyway, in all aspects of his life he's a drop kick, always getting into fights getting arrested etc) and I don't think she thought she is as high status as him. She has also told me more than once she thought I was too good for her cause I'm also pretty popular in my social circles (sorry, I know I just sounded like a wanker, just trying to set the scene a bit).
Perhaps I'm overreacting cause she has said countless times how she thought that she was happy when she was with him and comparing him to me she's so much happier with me and that he was shit etc. And I know for a fact all her friends and family have been saying to her how much better I am

But this issue is getting to me!
Thanks for the fast replies guys I'm really appreciating your help with this.