So the skylights are in. VERY easy. Second one took about 20mins first one about an hour. Things to watch. 3.5mm pan head screws need to be long (mine are 50mm although my roof is 9mm thicker due to ply lining so you might get by with 45mm) so special order for them! Jig saw blade needs to be long enough to cut both sides and they don’t make HSS ones with enough teeth per inch and also long enough to cut thin aluminium so a fine HCS wood one was used. Just long enough. On the second skylight I marked all the holes and then used a 10mm drill and then cut round with the jig saw. I cut centre to centre of the holes. Using the 10mm was easier than notching the roof as per the pics and the first one. Enjoy.