Stu, the only way i see an end to the fude over this subject is something on these lines....

Place a clause into Passionford that states 'no responsibility will be accepted by Passionford for any parts or cars sold by using passionford to advertise'. Then if you get any complaining PMS just delete them....saving you hassle.

Then, let Gold members advertise what they like, but only allow a certain amount of for sale advertisments to be placed...4 cars and then maybe 20 parts per year???..otherwise they have to pay per advert...just as you have to pay Autotrader or ebay.
Allow traders to sell as normal. They still get the banner benifits, and they get more space over non trader becuase of the 4 cars..20 parts limit.

Or something on those lines???? Just a thought m8