the photos and some other basic information will be a good start. A copy of some original paperwork should be pretty good proof that it is the real deal.
Ebay can be pretty tough if the seller is not savvy to the way things work.
You can also contact the newsletter editor (Rootes Review) to see what you would need to do to get an ad submitted. There are a lot more club members [who would see the newsletter] that do not use this forum.
Good luck.