I posted this earlier on the wrong account so here goes again...
I am seeing reduced upload speeds of around 15-25Mb all the time. 25Mb is rare, it is normally closer to 15Mb.
I have spoken to second line support, after waiting 1.5 hours and being transferred to 3 different people, to be told basically Virgin don't care about what upload speed you are getting it's not guaranteed and that there is no problem on my line.
Thing is, I have been told all upstream channels should be 64QAM, I have 1-2 channels at a time that are dropping down to 32QAM. Although second line support told me this is expected behaviour.... It was not like this when first installed so I find it hard to believe this is expected.
I have reset, tried different cables, devices, ensured the coax cables are connected correctly, tried with and without the attenuator fitted by an engineer for my old Hub 3. Still the same issues.