The chain Spinneys has an outlet down on the Dubai Marina and out of interest here are the prices for some items to compare to the UK:
Covent Garden Leak and Potato soup = AED 23.50 or GBP 4.70
John West Yellowfin tuna in a tin = AED 10.50 or GBP 2.10
6 pack of Coke = AED 5.25 or GBP 1.05
Then can you believe it...
Waitrose 8 rashers of smoked bacon = AED 32.50 or GBP 6.50
Waitrose sliced cheddar cheese = AED 23.50 or GBP 4.70
But you wouldn't want to buy any of that really as you can get instead outstanding fresh fish and shellfish there and some fruits I have never seen before called "Mangosteen" and also "Rose Apples".