a British kiddie book.
Those books are a perfect illustration of real life situations. Ha!
it talks about 'Kilo's'
That is why it is British! You must use metric measurements (grams, kilograms, millilitres or litres) when selling packaged or loose goods in England, Scotland or Wales. That`s the law.
The only products you can sell in imperial measures are:
draught beer or cider by pint
milk in returnable containers by pint
precious metals by troy ounce