See also
http://community.plus.net/forum/index.php/topic,1220... for updates
Going by the other link though, the average repair time at the moment is about 2-3 weeks. As plusnet only reported the problem to their supplier (BT Wholesale I presume) on the 7th of this month, I think we'll probably have to hang in there for another couple of weeks yet, however much plusnet kindly pester them for us.
Now that it's a confirmed exchange problem there's not much either of our ISPs can do except keep pestering BTW for updates.