"even if the FSG sets out all of the risks, it could be argued that it wasnt appropriate for an individual invetsor given their circumstances, so you might have some recourse against the individual brokers as well."
I'm not sure how successful that argument would be given the disclaimer early in the FSG that states OPES does not provide personal advice, has not considered your personal circumstances and strongly recommends you seek professional advice (this is paraphrased from the FSG).
Also, I think I saw somewhere that Opes may not be covered by FICS due to the nature of the products. I have no idea if this is true or not.