Beware! Ever more, the smaller Gunnera tinctoria is being marketed as Gunnera manicata. On this site the differences are clearly shown:
http://palmvrienden.net/gblapalmeraie/2017/07/07/gunnera-manicata-how-to-recognize-the-real-one/
At Bob Foltz’s botanical garden in Meeden, Holland I finally found the real manicata! This giant is getting a nice place beside the pond ..