Some of these I've heard of.  Others, well... not so much...

AUBERGINE - Eggplant
BACK BACON - Similar to Canadian bacon
BAKE BLIND - Bake a pastry empty by covering with wax paper and weighing down with beans.
BARON OF BEEF - Two sirloins in one roast
BAP - Hamburger bun
BEET ROOT - Beef (not beets??)
BISCUIT - Cookie or cracker (sweet biscuit or savory biscuit)
BOILED SWEET - Hard candy
BRILL - Something like a small turbot (WTF is a 'turbot'?)
BROAD BEAN - Fava bean
BROWN BREAD - Wholemeal bread
BROWN STOCK - Beef stock
BULLY BEEF - Corned beef
CANDYFLOSS - Cotton candy
CASTER SUGAR - Finely granulated sugar (not as powdery as confectioners' sugar)
CHANNEL ISLAND MILK - Milk that is almost as thick as light cream
CHICORY - Endive
CHIPOLATA - Small pork sausage
CHIPS - French fries
CHOCOLATE VERMICELLI - Chocolate sprinkles
CHUMP CHOP - A type of lamb chop
CIDER - Hard cider
CLINGFILM - Plastic wrap
COAL FISH/COLEY - Black cod
COFFEE SUGAR - Sugar in large brightly coloured crystals
CORIANDER LEAVES - Cilantro
CORN - Almost any grain (See maize and sweet corn)
CORNED BEEF - Canned pressed ham (See salt beef)
CORNFLOUR - Cornstarch
COS LETTUCE - Romaine
COURGETTE - Zucchini
CRISPS - Potato chips
CRUMPET - Something a bit like a English muffin ("English muffins" do not exist in England).
CUSTARD - Custard sauce or sometimes baked custard
CUTLET - chop
DEMERARA SUGAR - Light brown cane sugar
DEVONSHIRE CREAM - A particular type of clotted cream
DIGESTIVE BISCUITS - Something like graham crackers
DOUBLE CREAM - Heavy cream
DOUGHNUT - Jelly doughnut
ENDIVE - Chicory
FAGGOT - Meatball (I thought this meant 'cigarette'?)
FAIRY CAKE - Cupcake
FILLET STEAK - Tenderloin steak
FISH FINGERS - Fish sticks
FRENCH BEANS - Green beans or string beans
GAMMON - Large, thick round piece of ham
GARIBALDI - Hard rectangular currant cookie (see Squashed Fly Biscuits)
GINGER NUT - Ginger snap
GOLDEN SYRUP - Something like corn syrup
GREASEPROOF PAPER - Wax paper
GREEN PEPPER - Bell pepper
ICING - Frosting
ICING SUGAR - powdered (confectioners') sugar
JACKET POTATO - Baked potato
LIQUOR - (In some contexts, notably in eel and pie shops) parsley sauce
LIVER SAUSAGE - Liverwurst
MAIZE - Corn
MARROW - Squash that looks like a giant zucchini
MINCE - Ground beef/hamburger
MINCEMEAT - Mince pie filling (dried fruit, peel, brandy, etc; very occasionally contains meat
MIXED SPICE - A mixture of allspice, cinnamon, nutmeg, ginger, coriander and cloves
OFFAL - Liver, kidneys, tongue, trip and any other animal organs
PERRY - Hard cider made from pears instead of apples
PLUM DUFF - Plum pudding
POLONY - Bologna
PORRIDGE - Cooked oatmeal
PRAWN - Small shrimp
RING DOUGHNUT - Doughnut
RUMP STEAK - Sirloin
SALT BEEF - Corned beef
SILVERSIDE - Top round
SINGLE CREAM - Light cream
SIRLOIN - Porterhouse steak
SLICE - Bar cookie
SPONGE FINGER - Ladyfinger
SQUASH - Juice drink
SUGAR CRYSTALS - See Coffee sugar
SULTANA - White raisin
SWEETCORN - Whole kernel corn
SWEDE - Yellow turnip
TART - Pie
TOFFEE - Taffy
TREACLE - Similar to molasses
WHIPPING CREAM - Halfway between light and heavy cream
WHITE STOCK - Chicken or fish stock
WHITEBAIT - Small silvery fish, usually deep fried whole