I have never heard of them. I would consider avoiding them. If the car is tasty because its cheap, then its cheap for a reason. Its called "flipping". Kind of like houses and is something the Autoxchange are famous for.
Buy them cheap, do F**k all in the workshop, clean them and sell them for a pretty penny.
Judging by the article, avoid avoid avoid. Still, the fact he answered the papers question frankly means thay maybe he is ok.
However, remember he is buying them from private sales, dealers and importers so possibly he has no ability to service them, other than sell them.
As a Sales Person myself, I use the following phrase every single day "Buy Cheap, Buy Twice"