You will need to extend the leg of your isofix base using the red buttons either side of the support leg. This will create more room between your car seat and the back rest.
Galaxy Isofix : vehicle list (shopify.com)
Stratus Isofix: compatibility_vehicle_list_stratus.pdf (shopify.com)
If you need further assistance with this, please contact our customer care team who will be happy to help.