Please note under General Car Insurance rules : you are required to inform your insurer even if you do a private settlement (ref Onesg.motoring)

DO I HAVE TO INFORM MY INSURER EVEN THOUGH THERE IS NO DAMAGE TO MY VEHICLE?Yes, always report all accidents to your insurer no matter how minor the
accident may be, even if
there is no visual damage
or even if you have made a
private settlement with the
other driver.
This is because you cannot
be fully certain that the other
party will not file a claim
against you later.
You may find yourself in a
position of having your claim
prejudiced or declined later
by insurers.
WHAT HAPPENS IF I CHOOSE
NOT TO REPORT THE
ACCIDENT TO MY INSURER?
Failure to do so will affect
your No Claims Discount
upon renewal of your motor
insurance and will prejudice
your claim.