Please see the notes for the GWR Curchward D56 "right-hand-van" layout coach body former.
https://www.shapeways.com/product/7EKQ3LH5J/churchwardd56toplight-09
This model is for the mirror-image of that one, that is, the "left-hand-van" layout.
Please make darned sure you order the correct one(s) to fit the etches you have in hand to put on them.
When you view the corridor side of this coach from the outside and standing the right way up, the luggage compartment (van) is on your left, and the passenger compartments on your right.