jpeg1 is correct that you've got a problem with errors. You certainly could set up a Broadband Quality Monitor, but I'm not sure that's necessary, because in your case the error levels are very closely correlated with the power levels, and the power levels look marginal to me on too many channels. Also, channels 23 and 24 are doing fine, they've got single digit pre-RS (corrected) errors, and zero post-RS (uncorrected) errors, and that is sufficient to indicate that the hub uptime is not long, yet on the lower frequency and lower power channels there's millions of uncorrected errors. Those error levels will kill latency and speed, and make gaming and streaming difficult if not impossible.
You need a technician to visit and attend to the line quality, and if you give the forum team time they'll pick this up and get that sorted. You could phone the customer services number, but since rather too many of the offshore staff don't even seem to speak English, never mind understand the service they are supporting, I'm not confident that you'll have much joy by phone.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks