I have also come up with some different idea in which i can change some aspects of the story.
The main difference is on the actually character of the milkman. I have notice that the history of the character may need more of an explanation.
One way i can change the story is by showing that the milkman is an Martial arts expert who has escaped his home country where he was an 'elder' at a temple. He escaped because he destroyed the temple and the whole village turned to take revenge. He found England as a safe-haven and has been posing as a milkman ever since.
Another direction in which i could take the movie is to make the milkman into a vigilante. After he beats two of the friends, he then hears the story of the dilemmas the friends are in and decides to help them to beat the crime boss.
It not just the character that can change, i could also take the movie in a complete new direction. when the friend and the milkman have a stand off, the owner of the house is awaken by the noise and knocks out the milkman and the friend. he then locks them up in his basement and the two have to work together in order to survive.