I was hoping that someone could give me the measurements of the large baby beehind nappies? (Across the top left-to-right, and from top to bottom)

I'm currently using fitted nappies & PUL covers, but I really want to change over to baby beehind All-in-Ones. He's currently about 8 kilos, so I don't want to get the medium's if they'll only fit for a little while, but I'm not sure if the large will fit him just yet. I don't mind if they're a bit bulky, but I don't want them to hang off of him! lol. I'm going to get the smooth with velcro.

Thanks in advance!