I don’t think that the terms “Austin Champ” and “easy project” should ever be used in the same sentence. I’ve never seen one of these trailers for sale. Thanks to Bill for the link.
https://boston.craigslist.org/bmw/cto/d/franklin-austin-champ/7546177154.html
“Austin Champ 1951 to 1956 British jeep with very rare trailer motor turns not running easy project has Rolls Royce motor first $7000 takes them”