Yeah, the hub gets its reset button tickled any time it misbehaves. The T3 timeouts seem to have calmed down for now, but the post and pre RS errors haven't - with almost 1000 of both on each channel within minutes of resetting it. However TV signal is now good and broadband speed now also seems good. I'll keep you posted if anything changes.
The weird thing about the T3 timeouts is that they seem to happen in batches of several 10s to several 100s that according to the network log all happen in the same second.
Very odd indeed. But happy it seems to be working now.