Thanks.
I was in London a couple years ago and food prices at the market were more or less similar to those in California.
Of course, I have no idea if London prices are equal to those in the rest of England.
BTW, I was shocked that I was expected to bag my own groceries. I kept expecting a "bag boy" to show up and put the food in the grocery bag for me.
Some supermarkets do offer the service of bagging your groceries. Personally I prefer to do my own they mix up the produce and it takes me twice as long to put it away at home. Also they put too much into each bag and I have trouble lifting it. They are mainly packed by the girl or lad on the till (register) but sometimes they will pull staff off stacking the shelves to assist in packing if the store is really busy and then often you do not get the option of packing your own.
When supermarkets first became the main source of buying groceries it was normal you packed your own. It was stated that by you packing your own you went through the check out quicker so more groceries per hour sold so prices could be lower. The idea of your groceries being packed for you is another form of competition one chain offered it so all did.
The local mini marts still automatically pack for you basically because you still go to the counter rather than through a check out.
London prices for food are normally slightly higher than other parts of the country but then again it does depend on area to area but again with supermarket chains prices are more becoming the same nationwide.