Stories are nothing but just that, 99% of people have no clue what their usage is, so as soon as they see a reading telling them it's £xxx amount they start shouting the smart meter is wrong and it was fine before the meter was changed!!!!

Lol what?
No supplier worth their salt would ever leave a possibly faulty meter in place. Not without first putting a check meter in to verify readings.
If you are showing usage when your CCU is turned off then there is either something wrong with the meter or somepart of your install is wired incorrectly (crossed polatiry in most cases as CCU won't turn that off)