@Phil Harris ,that panel looks similar to mine but with the junction box on the back instead of the top. With it being a rectangle instead of round like the one that @Dieseldonkey has then i dont think the hole saw approach will work but it might sit inbetween the ridges on your roof (if you have any?)without too much of a bulge,similar to how @Deaky has fitted his. If it will then you will only have to drill a couple of small holes for the cables,good luck anyhow