I thought no examples were ever made and it was just a rendering showing a proposal?!
According to the period source I used ...
Published 1 November 1935: An example of the actual van is scheduled to be displayed at the upcoming
Commercial Motor Transport Exhibition (7-16 November) at Olympia, London.
Published 8 November 1935: "THE centre of interest of the Trojan exhibit this year is the new six-cylindered 20-25-cwt. van, which has been named the Lowdall. The concern is also showing two of its well-known Senior vans, and another new model, a light 10-cwt. van."
So it seems at least one example was built and shown in November, 1935.