The thing is the car has been damaged by a 3rd party and we only lease the car, so is not for us to make decsions on repairing it and who repairs it. If you did you could be breaking the terms of the lease. It would be different if you had done it yourself.
Often people want to do some sort of deal, not threw the insurance and then mess you about and as you did not report it. They report it first and then say it was you that drove into them.. I never trust anyone.
Personally i’d want it fixing as the damage was not caused by me, it depends how long you have still to go on the lease as well if rsa will do it now or when the car is returned.