This grower is sure of this plant identification.
This is the green variety of Ensete ventricosum, Ethiopian banana, which is hard to source in the UK, I grew it from assured seeds from jungleseed.co.uk. Not winter hardy in the UK, but if you cut the leaves down to bring it indoors for the winter it will grow back in the spring. Will gain several metres of height if continually repotted.
Abyssinian banana, Ensete, Ethiopian banana
Ensete ventricosum (Abyssinian banana). An upright, palm-like evergreen perennial native to tropical Africa. Bears red-green, spoon-shaped leaves. grown for its showy inflorescence which are droopy spikes of red bracts in late spring. The fruits are banana-like but are not edible.