I am now getting 7-11 Mbps on the speed tester, which while better than the 4 I was getting since fibre enabled last week ( he said it was because there was a filter in the box), its not what you could call fast is it!
Are you using 5Ghz? Also do you have a type A or type B router - it should say on the base of the HomeHub where the SSID etc is.
The Type B has a known issue where on 5Ghz, the wireless speed often gets stuck around 10Mbps. There have been many fixes for this, but the only ones that really work are to reboot the device or to manually change the wireless channel on the fly when the issues crop up.
The type A does not exhibit this issue. Hence why I am keen to find out which model you are using.