Oh, I should have mentioned that on the habitation door side, there are extra screws/brackets and an aluminium trim round the bottom part of the doorway to remove. Also, this piece is very long, BUT has a thin, weak point half way along (where the doorway and step cutouts are). I would recommend either rigidly supporting this weak, bendy centre section (piece of wood and gaffer tape, maybe?) or have three people handling the removal.
Good luck!
Barry