Been through this myself and it’s really easy if the insurer accepts it as no repair needed then that’s it done. IF you get the repair done and pay the excess then you will not get GCB as a claim has been made at cost to the insurer. The excess might be £100 but the total cost will be far higher.
Never go against what the insurer tells you it’ll end badly, you’re even advised not to use touch up pens etc.