Here's the answer chaps - it can all be done online for 29 euros.
http://www.lenevette-assurances.com/contrat.php
Select the option for
Responsabilité civile Circulation AUTO for 29 euros.
You will need to make a new account for yourself - name, password, date of birth, address etc.
Fill in the circuit as:
Date: 19/09/2104
Nom de Circuit: Autodromo di Modene
Department: Italia
Votre véhicule:
Marque * Maserati
Modèle * Whatever the model is
Année * Whatever year the car is
Immatriculation (ou N° série) * The registration
N° de permis * Your driving licence number
Click '
Suivant' (Next)
Check everything is correct, and click '
Acceder au Paiement'
Fill in your card number as normal and click on 'valider' - this page has an English button if it helps!