I remember reading when I was young a book that I can remember most of the plot of, but not the title.

It was about some children in Liverpool in the early 1970s.

They are in a band of sorts & when the guitar player damages his instrument they need to raise the money to get it repaired.

By various means they try this, including one of the younger ones busking by banging on a drum very loudly in a shopping centre & nearly getting in trouble with the police.