My gas smart meter was massively over-reading from the day of installation. Unfortunately the matter was complicated by the onset of Covid
Long story short, I ended up in a six-month long battle with the energy supplier and the Ombudsman (who were completely clueless) which, only thanks to my persistence, finally resulted in me getting a very large refund.
Reminds me of my mum battling to prove a dodgy gas meter way back in the late 60's, we'd watched it jump as the next needle rotated (remember those ?) the gas board wasn't having any of it, so a relative set up a cine camera on a tripod for proof
