At last I've found the name of a (neighbor's) leaf I sometimes use, in case anyone is looking for another large-leaf plant to cast. It has lots of names.
Petasites japonicus giganteus, aka Fuki, aka Giant Japanese Butterbur aka Japanese Sweet Coltsfoot.
It grows here in NS like a hot damn, very hardy and comes up year after year. it has a lovely slightly furry textured underside that produces a somewhat a milder version of Gunnera, but the leaf is much softer than a Gunnera.
Just in case anyone is interested in looking for more large leaves...
🤗😁😃 oh how I want to grow this in n.z. Probably not allowed over here. Will look into it but don't think so. When will your castings be ready from this leave Lahave, look forward to seeing them. 🤢 So want this plant.