Good advice thanks @Grim Reaper it is simple enough to go back and seal them up around the rivnut joint.One thing to check, seal the ends of the bolts that protrude through from the sliding door rail, there were a few allowing water in on mine that I sealed up with PU adhesive, I was getting water in the bottom of the cavity behind the wheel.
I use a pressure washer, carefully but its probably a source of water in areas that are not designed for it.
The multirail roof bolts are already leaking! Another job on the list.
The nice thing about the insulation used is that it is all water tolerant and wont soak it up or break down. That's the plan anyway. I have also left a channel gap at the bottom rather than stuff wool or foam right down and plan to put 100mm vents in the bottom rear corner of the side panels.
Hopefully for ventilation but also to help the slam vents to work and make it a bit easier to close the doors. Nothing more irritating than repeated door slamming.