An important consideration for the installation of a Solar PV system is planning permission - which is something you have to sort out for yourself.
The good news is that in most situations the installation of Solar PV on a roof will be what is known as a 'permitted development' and, so long as specific conditions are complied with, planning permission is not required.
Looking at the key conditions, I had worked out that my property was not in the formal Conservation Area of Marlborough, and the short listed suppliers I was talking to could self-certify that their work complied to the necessary building regulations.
However this was clearly a complex area and as I wanted to be quite sure, I contacted the county planning department who were very helpful. As a result I submitted a formal enquiry, which was subject to a small fee, where I had to define the type of installation I was proposing and its details. What proved useful here was a schematic diagram produced by one of the potential suppliers which is shown above and because I could submit all my information via email there were no delays in the post - and in a very few number of days I gained confirmation that it would be a 'permitted development'.