Location Nottingham Cityfibre 900/900
Live BQM
Remarkable similarity with the Minimum Latency last night between your BQM and mine (also aligns to last nights football, but that's probably a coincidence!?)
I'm guessing that as you are not that far from us (but not close enough to be on the same CityFibre infrastructure), you also connect to the Vodafone Birmingham gateway 84.65.192.1 which could explain the likeness and firmly puts the issue with Vodafone.
How to get their support to recognise this on their "flowchart", I just wouldn't know where to start though! Mind you, your minimum speed is below the guaranteed for a 900 line, so that might be a good place to start?