Hi - I have just bought a standard C channel awning rail from Funky Leisure. I now want to fit it on my T6.1 and be leak free. I don't have any roof rails and this will just be fitted in the gutter on its own. The factory blanking bolts have rubber washers on them. For fitting do I need to place the rubber washer below the awning rail and then just use the original bolt to secure the rail. Only possible leak path is then through the bolt as it goes through the rail and rubber washer. Has anyone else put another rubber washer on top of the rail before securing?