Whilst I had spent time calculating power requirements, battery storage and the Watt hours that solar panels of various sizes can provide, this is at its very best, theoretical.
I only have so much room on my roof for solar panels I have no room to transport additional portable panels and only so much space to store batteries.
The runners for the roof bars restrict the width of the roof panels that I can install and I want to retain the ability to store some light stuff on the roof, at the front using roof bars (without casting a shadow on the panels and restricting power generation).
I also wanted flexible panels as these are lighter and can fix directly to the roof, thus keeping weight on the roof to a minimum, important as we have to lift it regularly to access the sleeping area.
After the usual research, I found a 200w panel at Photonic Universe which fitted exactly between my roof bars and was self adhesive, so less messing around with sealant during installation. A bonus was that the panel was manufactured in Austria and not China!
The Solar Panel Installed 
Wiring Block
The panel was installed with the wiring block towards the front, so that the cables can more easily be passed through to the interior. Strangley, some flexi panels have the wiring block in the back, so it pays to read the small print.
Next time I would get some help positioning the panel on the roof, as once the adhesive touches the surface, it is not going anywhere; I had to tale a small slice off of the right hand side just to make it fit correctly. I will add Sikaflex to the edges to ensure that water does not get underneatht the panel.
All that remains is to connect up the wiring and fit a Scan Strut waterproof grommet where the cable passes through the side of the roof.
Fitting the Scan Strut 
Then add some protection to the worres and we are all done. I will finally secure the wires to the roof bars once I know there final position.
The scratches on the paint were as a result of removing the front roof rack and will be sorted when the rack is re-fitted.
All Done!
48 States of Gray 