It's a sort of kimono style with a collar and tie belt.
Am I completely bonkers to think I could wear it as either a wrap dress or unbelted as a sort of duster coat? With a black long sleeved tee, black leggings and black boots.
This is the one. onehundredstars.co.uk/collections/gowns/products/copy-of-one-hundred-stars-kew-rbg-passion-flower-grey-gown
If it helps, I'm very tall and a reasonably proportioned 14.