I'm not sure if there is a difference for halls or specific regulation in Vaud, but in Zürich if you rent a room or flat you need to have an insurance for the property you are renting. So i would asume that your british insurance will not cover this.

If you do not reply you will most likely receive another 1-2 reminders, they will start to contain information what happens if you don't get an insurance.

I would call your Landlord and ask