Things I observe here:
1) Mule like obstinacy from VM, so that it has taken four months to force them to admit that they have sold more contracts than their network can support around you (and not that far from VM's glitzy headquarters), despite the problem being identified by a forum user within three hours of your original post back in February.
2) When this started you were on 350 Mbps. At some point you chose to upgrade to 1 Gbps (?), showing that firstly a Hub 4 on its own, with more channels and higher modulation isn't going to address over-utilisation, and secondly that VM are continuing to sell speed upgrades when they know (or should know) that the network is at capacity.
3) I'd say you now need to raise this as a formal complaint if you haven't already, wait to be fobbed off, and then escalate to CISAS asking for compensation under every possible heading. I suspect that CISAS would readily wring several hundred quid out of VM, and an ongoing discount for the faulty connection, that would go some way to cover the costs of a slow ADSL or VDSL line for gaming and latency sensitive purposes, whilst keeping the VM connection for heft downloads and non-latency sensitive use? If you do this, the complaint to VM needs to be long, precise and detailed, to specify exactly what you regard as an acceptable settlement, and to request a deadlock letter if the company can't immediately agree to settle on terms acceptable to you.
I'll flag for the forum staff since this matter could easily go to CISAS, which is slow and tedious for all concerned (as well as costing VM hundreds of quid in case fees), I'm not sure whether the forum staff can expedite an acceptable settlement, but worth a try.
