What’s it to be? A glossy red ‘chubby heart’ cake filled with the lightest of chocolate mousse? A slice of celadon-green and primrose-yellow Battenberg? A ‘cartwheel’, her luxurious take on good old Wagon Wheels? What about a plate of those little biscuits exquisitely iced with edible first-class stamps? I am with Anya Hindmarch, 52, handbag…