I wasn't very happy with the sides of the wagon or the thickness of the main doors, so I added an armoured skirt of Renedra 20mm square plastic bases around the lower section, which I think looks much better as a result. I have loads of these plastic bases spare, as I only use mdf and metal bases.
I also found the little metal star sequins that I used as Soviet stars on the old armoured train that I built a few years ago, so I've added these to the doors as welded on insignia. I still need to attach the toy train bogies and add some sort of coupling gear but otherwise this is a done deal. Oh well, back to work!