Charge for supposed tyre damage

My wife and I recently hired a car to drive around England. On collecting it the first thing I noticed was that it was dirty and in particular the rims being dirty with brake dust. However when you want to get going you tend to keep quiet. Supposed damage to the left front rim could not be found but I later found it on the right front rim. some body damage recorded was rubber scuff marks which I later removed with some polish before returning the car. Also the car had only done 12,000 miles and the tyres seemed too worn for that distance with one of the front actually being illegal as it was worn down on the outer edge to below acceptable levels. I spent two years as a Police crash investigator.
On returning the car to the airport the attendant pointed out a screw in the centre of the tread on the left rear tyre. The tyre was still fully inflated. They later charged my credit card for the tyre to be replaced with the invoice showing that the tyre was not repairable due to a torn/slashed sidewall.
I have since cancelled my credit card to stop any further fraud and am about to make a formal complaint to their industry ombudsman. I guess I am actually lucky as I only lost about $200 Australian.
Two work mates are luckier as they are visiting the U.K next year and want to known what hotels and other things I would recommend. Obviously not Europcars.
Whilst I don't hold out any hope of recovering the money they stole from me I am comforted that of the many thousands of dollars that I will spend on hire cars in the future none of it will go to Europcars.