Thank you for choosing the small guards van, you have done a good job finishing it, great to see others peoples versions of the models.
I have used the "N" gauge 9ft wheelbase wooden type chassis kit by Peco, which I have got from Parkside Dundas. just remove the couplings if you are going use Bemo or Greenwich type and add the weight in side the body on the floor.
I hope this helps.
please let me know if you have any other questions.