The Kale Park would be a good place as it as lovely views. Also for a really special night Red Island. However, most of the restaurants in Calis have lovely views and if you give them a bit of notice they will pull out the stops to help you celebrate. It was our Wedding Anniversary in June and we mentioned it at Georges Restaurant, where booked a slow cooked lamb claypot. The night of our anniversary they had saved us a table which was beautifully decorated and they even bought us a present. You are lucky to be coming to Calis as all the restaurants will give you a super special occasion service.
Jacqui.