Thanks for the replies ... yes, I am expecting a new modem when they actually get round to doubling my speed (was meant to be in June, now they say end Dec). Good to know the superhub supports modem mode. At the time I could have upgraded from 20M to 30M I held back because the superhub couldn't function in modem mode and I really didn't want it as a full router.
No problem with my current router, it's a HP MicroServer
I'll see how it is this week and place a call to support over the weekend if it persists, it seems odd (to me, but I don't get all this cable stuff) that at the same power levels I get full speed during the day.
Otx, afaik I'm on a Lewisham UBR (hostname begins cpc16-lewi14-2-0) and a traceroute takes me through bmly (bromley?) and brnt.
Cheers.