Puzzle for the Secret Seven

‘Hallo!’ shouted a voice over the wall, and Scamper barked loudly at once. Peter and Janet looked up from their gardening.‘Oh, hallo, Jack!’ said Peter, pleased. ‘Stop barking, Scamper! Anyone would think you hadn’t seen Jack for a month. Come on in, Jack. Any news?’‘Yes. Rather nice news,’ said Jack, wheeling his bicycle in at the front gate. ‘My mother won a pound at the whist drive last night—and she’s given it to me to take all the Secret Seven over to the fair at Hilly-Down today. Can you and Janet come?’‘I say—how decent of your mother,’ said Peter, and Janet beamed. She had so badly wanted to go to the fair, but she and Peter were saving up for their father’s birthday.‘There’s just one thing, though,’ said Jack, seriously. ‘Susie will have to come too—and she’s got an awful friend staying with her, called Binkie. Mother says the money’s for them too.’