Martin Lewis' data-Crunch: What's the UK's best salt 'n' vinegar crisps?

The joy of good salt 'n' vinegar is you bite them, and they bite back – the flavour needs to be strong, sharp, and leave your tongue feeling like sandpaper. So it's time to focus MSE's data-crunching expertise on to the ultimate investigative challenge... finding the UK's best salt 'n' vinegar crisps.