There is just one little thing that is not explained. The two kids are sent to Manchester with a bag with some mysterious goods inside. They arrive, meet the Manchester gang who take the bag and give them another bag, with also some stuff inside. It appears after the two kids are back to London, and after their fake assault in the street, that the bag they brought from Manchester was full of blank notes instead of cash. So the question is: Did the Manchester goons try to cheat the London gang? Or was is only, for instance, flour in the bag that the two kids initially brought to Manchester? Was it just a test to see if yes or no the two kids deserved to be trusted?