Yes there was v. minor damage.
I believe it was there prior to me picking the car up, along with at least 2 other similar marks on the same side, none of which were noted on the form at the time of picking up the car. The two other marks, which I would describe as dings, were actually more noticeable, the mark I am being charged for is more of a crease and crucially was marginally longer than the golf ball check that Enterprise say they use to determine if a mark is chargeable.
Enterprise say that this one mark was additional, the two others were existing and thus want to charge me for the repair.
Since all of them are too minor to actually photograph, my photographs cannot prove that these marks did/did not exist prior to me picking up the car.
In the absence of being able to prove the damage one way or another, I am now disputing that the repair costs are excessive (if indeed they have been done at all)