Well strangely today my download speed has jumped up to 72mb. It's been around average 50-60 over the past 8 months. I test it pretty much 2-3 times a week and always around that mark so why the sudden jump up to almost the max speed I had a year ago when fibre was first installed? Could something have changed at my cabinet? I haven't made any changes at my end. Hopefully it stays this way but who knows.

I have a similar experience- however on a significant number of occasions that I drive past "my" cabinet there is an Openreach van and man working in/on the two cabinets. So it is never a steady state, plus Virgin have been doing a marketing push in the neighbourhood and they may have reduced the traffic/interference on the BT lines.

Mine also jumped back up to 38mbits down and 12mbits up a few weeks ago, which is close to my initial connection speeds over a year ago, which was nice as that small increase makes quite a difference to download speeds. No idea why.

Could be part of the vectoring trials (gradual rollout).

My speed jumped back up to its (banded) 66999 (attainable currently 71504) sync on 12 April and has stayed there since. Last time this happened it only lasted a few days.