Same for me as well. Phoned the tech support line and jumped through the usual hoops (reboots of the SuperHub, Factory Reset of the SuperHub, speed tests over Ethernet + WiFi) as there was nothing showing on the service status page. They are sending a new SuperHub out to me as the tech thought that that may be the issue.
Looks like it's improved a little since yesterday night, though 20-30Mbps on a SuperFibre70 line still seems a bit of a rip off to me for off-peak times.
Will have to wait and see if the new SuperHub makes any difference when it arrives later in the week.
this tweak helped my pc broadband speed increased : [only works if your network card/ethernet adapter can handle 10/100/1000 Mbps]
DO THIS AT YOUR OWN RISK.
go into network settings change adapter options click on ethernet look for properties and click configure go to advanced then click on speed and duplex and change value to 1.0 gbps full duplex then ok to save.
if you make a mistake you can reset back to your old settings