A 'Mobile Home' advert found on Trove from The Sun 25 September, 1938. This one might be the same one in the photo on the first page of this thread, big windows! Dare say the 6ft version may have had smaller windows

Details are hard to read, hopefully a clearer copy will turn up, but some features; all-steel body panels, two-color washable duco, dustproof floors, gay coverings and automatic braking system.
George