The appeal courts in the UK hate overturning decisions of lower courts; you have to have a pretty rock-solid cased to get to appeal. I'm not aware of an appeal

The appeal courts in the UK hate overturning decisions of lower courts; you have to have a pretty rock-solid cased to get to appeal. I'm not aware of an appeal court ever overturning a whole class of convictions. I can imagine an appeal court ruling that some accounting system produced unreliable evidence; but each affected case would then probably have to go to appeal.