I've been having awful broadband speeds, even lower than 5mb on regular occasion at peak times. I have infinity 1 and have always had intermittent problems due to a poor quality copper line underground to my property (as noted by the outreach engineers).
But recently instead of being between 20-30mb like the past 6months, I've been on 10-20mb regularly, which is rubbish for a family house.
I have been told to try a vpn by a friend to see if I'm being throttled. A VPN is doubling my speed.