We have a single storey flat roof extension at the back of the house.I find it very dark and have to lights on even on the sunniest days. Have any of you had sky lights fitted? How much were they and did they make alot of difference. We need to increase the light in the extension itself and the room adjacent to it that has been knocked through so the extension and original dining rooms is an L shape with the horizontal line of the L being the extension. Hope that makes sense!