The angle looks to be about right for summer use, about 15 degrees below latitude, but for winter water heating they are going to loose quite a bit.
I know - we are around 45 degrees north (near Bordeaux), but just about every roof round here has the same pitch & without messing around a lot, simply bolting some 6 by 2 (to which the panels are screwed) to the roof structure under the tiles, was by far the easiest mounting option.
I bought a job lot of 10 20 tube panels on flea bay for £1,500 & the other 4 panels, I am either going to put on the house roof (same angle), or mount against the wall under the current setup at 90 degrees to the midday winter sun. Hopefully 200 tubes should give us all year round DHW - My main problem, i suspect, is that as I will have over 40M of pipe run to the thermal store in the house, which you can see on the right of the 1st picture, the thermal losses will be a significant factor.
The underground pipe run is already in place (15mm tube enclosed in 9mm armaflex, inside 35mm bore 19mm wall ordinary insulation, inside a 90mm drain pipe), I just have to change the current immersion heater for a thermal store & away we go.
In the summer, I will have way too much heat, which I can dump in the swimming pool & in the winter, even on the shortest days, I hope 200 tubes should be enough to give us (2 adults) enough hot water.
