Just managed to get through to the call centre. Apparently there's a server problem further up the line which is being worked on. ETA on fix is sometime in the next 24 hours. I'm in Bristol if anyone else down here is having similar problems. I don't think it's noted on the service status page.
Can you set up a Broadband Quality Monitor (BQM) atthinkbroadband.com - this will give you an insight into what is happening with the signal at the other side of the Hub, it will take a few hours to get any kind of trend showing although you can post the link straight away.
Post a link to your BQM on here.
Instructions for posting BQM Link
Under your BQM graph are two links in red.
Click the lower link (Share Live Graph) then click generate.
Copy the text in the Direct Link box, beware, there may be more text than you can see.
On here click the Link icon (2 links chain to the left of the camera icon)
In the URL box paste the link you copied and then click OK - you can post the link straight away.