I'd like to say a big public apology to Welshamethyst and Salamander because I've seriously let them down on the support front. I thought I had fixed their problem a while back but I didn't communicate that with them, which if I had, it would've given them a chance to tell me that in fact I had not fixed their problem at all.
I think I have fixed the problem and I'm hoping to hear back from them both to see if I have. If not I'll look further, but I did find an extra setting on the server's firewall which looks like it could easily have caused them problems.
I'm also aware that for some odd reason, followers of Yetzirah are still receiving notifies that have no link. That's extremely strange because everyone else's notify mails have links, and indeed for about a day, so did Yetzirah. I'll be trying to take this up with Yetzirah again shortly and I'll also be checking the code to see if I can see what's going on.
Once again my apologies to Welshamethyst and Salamander. If I've not found the source of your problem with my latest change I will look into it significantly quicker this time!