As noted earlier:Would it be possible to salvage the floor from the Leaf and transplant it to the Golf?
A Leaf floor obviously won't fit a Golf, but a similar shape could be custom-built, even using some of the Leaf floor panel. The Leaf has 300 mm (a foot) longer wheelbase than the Golf, so even with a custom floor the Leaf pack is unlikely to fit intact - either the back end runs into the rear suspension or the front end blocks the front seat footwell, or both.