have you asked for a report from a garage?
sorry for the delay.
I presume you have reported this to your insurance company?
You need to check your insurance document carefully. You may well be under an obligation to report anything within a time period.
You can try to settle this privately. It would be helpful from the point of view of your no claims bonus.
However, she could always demand your insurance details. It would be an offence to refuse. If you cannot negotiate something acceptable it might well end up going through insurance.
If you want to avoid this going through her insurance I would pay them off in full quickly.
If not, tell your insurers.
Can I clarify anything for you?