Peter Le Feuvre

Hi, I have had solar panels installed on my roof, but due to delays installing a three phase electricity supply, the builder has not been able to install an invertor or connect the panels to the grid. As he is finishing the build he has charged me VAT on the solar panel installation because because it has not been connected or commissioned yet. In VAT Notice 708/6 installation is defined as permanent fixation, which the panels are. As the panels have not yet been commissioned is the builder correct to charge 20% VAT, or should he be charging zero rated VAT because the panels are permanently fixed to the roof? Kind regards