Interesting that the dealer is getting off so lightly in the comments so far. If you present yourself as an expert in something, what is your responsibility to the client?
If this were art, and Mr. Dowling represented to the buyer that the piece was an authentic and original de Kooning (for example), but then proved not to be, would we be putting the onus on the buyer to do their own due diligence?
What the the premium which Mr. Dowling undoubtedly charged the buyer for if not for expertise?