How does add Boone apologize to Christopher after their fight?

From the text:

The next day Father said he was sorry that he had hit me and he didn’t mean to. He made me wash the cut on my cheek with Dettol to make sure that it wasn’t infected, then he got me to put a plaster on it so it didn’t bleed.

Then, because it was Saturday, he said he was going to take me on an expedition to show me that he was properly sorry, and we were going to Twycross Zoo.