so i can answer this cause it happened to me in first week too
It took fix auto like 2 months to fit my car in for repair so i had a courtesy from Enterprise, when the car is ready to be repaired the garage will ring you and you have to pay the excess which is £100, then the repair is started, when its ready they’ll let u know, u can pick the car up and drop the courtesy car off the same day
Nothing extra needs to be paid