The number of panels on the roof was under-estimated in the original survey so when the fitters arrived they were able to fit another 2 panels easily on the roof and bring to the full 4KW, but caused a delay getting the work finished off. We had a succession of dates for the fitters to do the work and at the last minute they were not available and we had to keep re-booking. This happened 3 times which was very frustrating since required arranging time off work to be around when the fitters arrived. Whole process seemed quite chaotic with a lack of communication between fitters, us and the head office. A number of roof slates were broken when fitting which I had to report and then wait a few weeks for same fitters to be available to replace. Would have hoped fitters would have been aware of the broken slates rather than for me to see them afterwards. System seems good so far hence given overall rating normal, but fitting process poor.