I took a chance and clicked on Create Label.  Option for Express Post but had to but my own packaging measurements etc.  I just used a plain 500gm satchel and then I chose signature on delivery as an extra...all good.

The label was in black and white, Express in Black at the top of the label so I asked the lady at the post office to put some yellow Express stickers on it for me.....she did...about 10 of them!