Try these people.
http://www.thisismoney.co.uk/complaints
To be honest.., its not really hard with various car insurance comparison websites to find your own car insurance. At least then u know what goes on the policy. However, I would imagine the FA sent u a copy of the policy document and I'm pretty sure the insurance company will say u had an opportunity to correct any errors, altho I am also sure u will have some come back against the FA if u can prove u gave him the correct information.