A grocery store that specializes in frozen food, this location of the Food Warehouse in Southampton, UK provided a large selection of frozen meals and ingredients for locals. All of it didn't apply to us visitors, but they had a non-food section as well. It seems like they have items that have a long shelf life (so little produce or the like).
We were able to pick up a local brand of laundry detergent sheets (branded Dr. Beckmann: 40 sheets for 5 quid ) that we intended to use to do handwashing of our dirty clothes while on our long cruise. We had picked up sheets on Amazon, and we found that detergent sheets work a lot better: compact, easy to measure, and can go through airport security easily.
Checkout was similar to a checkout line in the States, and the use of credit cards was accepted and had no fees. read more