It's a fairly specialist item, so it might take a while to find the right buyer. Many of the cars for sale website will also take listings for books and manuals, so that might be worth a go. You could also have a look on social media platforms such as Facebook to see if there is a Daihatsu-related page (Facebook also has a sales section). Finally, you could write in to the classics magazines and newspapers which still carry classifieds and for sale items.