I have shopped at Sainsburys in the past. I always compare prices (in any shop) by looking at the price per kilogram. Sainsburys, however, tag (say) the price of their different types of strawberries (British, imperfect, organic) one per kilogram, one per pound, and one per punnet, so comparison is impossible. This system applies to a number of items, not just strawberries.
I've brought it to their attention in store, I've contacted the store manager, I've written to the CEO all with no result. I brought it to the attention of a food programme who ran a piece on it and interviewed a Sainsburys executive about it, who promised to standardise pricing across all stores.
The result? Absolutely nothing has changed! I've given up and gone elsewhere.