Thats interesting that its not hitting all BT customers, i think that would imply its something in there ISP Routers, since these are all high end jobs, it might be a bad protection filter, i know little to nothing about them but apparently alot of ISP's use filters that search for known torjen or virus signatures and well disconncet the connection they are comming through on.

Maybe a miss directed attempt at removing "evil" dcc sessions is catching there customers. If this is the case they may well be unaware of it in the sence.