Places to visit in London: The Burrough Market is a must. Situated underneath London Bridge it is entirely a food market that contains stalls dedicated exclusively to cheese, olives, poultry, pork, olive oil, pesto. There is fresh fruit and vegetable for sale as well as pastries, turkish delight, home-made jams. Almost all of the stalls have samplings available and the vendors are friendly and amusing.
Step over the road for a coffee at Montmouth cafe - the line up is long for a reason. A latte, cappucino or flat white will satisfy all coffee lovers.
Have a random chat with another market-attendor about the preserved pig's head on the barrel by a meat stall. Ask the jam vendor what exactly the difference is between jam and jelly. Walk repeatedly past the same stalls for more samples - the burrough market is a joy for all!