"Most customers are now back online, however despite our best efforts some customers are likely to experience performance and speed issues following this. This is due to some areas of our network being oversubscribed whilst others are undersubscribed.
To further redress this problem, our engineers have begun work to balance the network, as a result of this you may notice a very short disconnection of your service whist we continue to do this work into the evening. We have also requested that our suppliers make some temporary changes on our behalf to help bring things back into balance." Seems to indicate to me, the the "BTW Service Outage" was the result of Plusnet Selling it cheap and piling them high in their limited bandwidth. Twice in as many months and the only ISP I have had to drop service it is possibly time to move on.
We have connections with Plusnet and BT at our office and only the BT one dropped, the Plusnet one stayed online. But having said that, it only seemed to be customers with Plusnet connections that phoned to say they were offline.