You are obviously in the UK, the same as what I am, have not experienced this before, when I order books and it is just one book it arrives with the postman, like one did this morning, if I order more than one book like I did a while ago, it still came by Royal Mail, but with the post van. I also order by free delivery, the book I ordered on Sunday, was sent out yesterday and arrived today, so I feel it is hardly worth paying for delivery on books.