History / Why Cross of Valour with 2 bars was awarded to my father (Miszczyk / Bradley)? [5]

My father Alojzy Miszczyk ( later Bradley ) was in the 1st Armoured division during WW2 , he was awarded the Polish Cross of Valour with 2 bars . Like many soldiers returning home after the war ( He settled in Scotland) , he did not talk at all about the war. I am interested in why he received this medal with 2 bars . I want to be able to tell my new grandson all about his great grandfather !