Unprofessional-ism at National General Insurance

I think the OP has a valid point and they should pay up.
The RV was not "under a conditional sales agreement by us to another".
That is entirely different from being on consignment.
So GS, it's up to you to prove there was a "sales agreement" (a legal term BTW) to another person - not that it was just "for sale". If you can prove that then you can deny the claim.