Saturday. 10am. There's a knock on the front door.
"Me and Freya are opening an art gallery," says Grace, 6. "Come and buy a picture."
I go over with Cassady, 5. The girls, very excited, are sitting outside Freya's house, with 12 paintings arranged on a table.
"Pictures are one pound each," says Felix, 8, Freya's cheeky brother. "Actually, two. Actually, three." The art is rocketing in value. I'd better buy something before I have to remortgage the house. "I'll take that," he says, grabbing a tenner from my bag. He's obviously the gallery manager, and he's showing talent: he's not afraid to steal.
Hmmm. Oliver James would probably say that, if I give money, it'll teach Grace art is only worth doing for cash.