I'm sure people in Scotland would probably say the same about the London server, although in many cases you might find their traffic comes down to London anyway. This is kind of what this tool will help us uncover 
Not sure if this is the sort of thing you're looking for... up until last night my BQM's from London and Edinburgh, both IPv4 and IPv6 were all essentially identical apart from the higher base latency from Edinburgh.
Then at 8pm, Edinburgh v6 showed a slight increase in latency, along with a red spike which has repeated every hour on the hour since then.
It didn't show on the Edinburgh v4 until 10pm, with a red blip rather than a spike, then just after 11pm it went back to normal.
Nothing much visible at all on either of the London BQMs. I'm with IDNet FTTP and (I think) Zen backhaul, so likely Zen shuffling their routing tables?
Graphs:
Edinburgh:
IPv4,
IPv6
London:
IPv4,
IPv6