Because really they want £40+vat so they say £47 to make it sound a better deal
Before they done it this way, and they used to say "£40 each" they were cheating you really as it is like when you shop in makro and it says "only £99.99" but after vat it is £117.50
That really annoys me and would prefer it to be inc vat prices quoted, at least you can see where you are already