Title of book

[john2tzh]

Can anyone help me with the title/author of a short story I once read and would like to find. I think it was by a well known author although perhaps not known for their short stories. As I remember it concerned the directors of a famous auction house and one director wronged another. The daughter of the wronged director had an Italian old master forged and then overpainted with a still life of some birds. The other director heard of the hidden old master and bid a fortune for it. When the stil life was cleaned off the old master was there but it included a donkey driving a 4wd. Someone help please.

[Pressgang1]

I think it's The Art of the Matter by Frederick Forsyth