For CGU: You will be sent a renewal letter around a month before your current policy is due to expire. The letter will include your schedule which outlines any changes to the terms of your policy or the premium payable. If you have set up automatic payments your account or card will continue to be debited and your policy will be automatically renewed. If you have chosen not to pay by installments, your schedule will provide options to pay.
For Zurich: Your policy will continue indefinitely until a claim is made, on the basis you make the necessary payments until your set limit is reached. Once the premium paid matches the sum insured you stop paying premiums altogether.