ruby murray = curry
barnet fair = hair
currant bun = sun
hampstead heath = teeth
deep sea diver = fiver (a monetary note)
mince pies = eyes
china plate = mate
pen and ink = stink
septic tank = yank (a person from the U.S.)
whistle and flute = suit
don't worry bayboy
cockney is probably the least spoken language of that area of london why not try to learn words from a more common foreign language which will be more useful to you should you ever visit the area