Morrisons, although we do have a few gripes with that place.
1. grim ordered a veggie breakfast only to find they'd popped a bit of bacon in it.
2. once you've done a full shopping load and then discover you've forgotten one item, you're not allowed to pay for it at the ciggy kiosk. On more than one occasion I've looked back at the main queue and decided it's easier and quicker to just walk out brazenly with the unpurchased item on top of your trolley.
3. oh another shoplifters tip. if you put more than 1 bouquet of flowers into the plastic bag, the checkout assistants will probably only scan one item.
hope that helps your market research!