Here I will discuss a few of my favourite places to buy food and drink in the town.
Head to K-Mart (71-73 High St) first for a well stocked selection of Korean goods. Stock up on big bags of rice and buy some pre-packaged noodles which are very cheap and tasty. Also get your sliced beef for barbecued bulgogi and sliced pork belly from the chiller cabinets. Whilst here purchase some Soju, the drink that Koreans drink at dinner, on nights out and when they want to get drunk. I also like the Ghana chocolate which is smooth and very creamy.

Near to K-Mart is Jin Mi which sells sushi and has a buffet where you can purchase hot food to take away.
Seoul Plaza has a large site on the high street and another by the Fountain roundabout. Purchase portions of bibimbap ingredients (2.50) and freshly made pickled vegetables, as well as fish cakes and marinated squid.

Above, a selection of products available in the K-mart stores. The meat and fish are always packaged and presented very cleanly and neatly. Oxtail may not be popular on British dinner tables but is eaten a lot by Koreans along with brisket (feather steak).
And note the many varieties of canned cold coffee on sale.
Thanks to the kind people of K-mart who allowed me to take photographs of the shop displays.