a) Permanently lower the height of the roof to its original ridge line so that it is uniformed with the other terraces on the street; and,
b) Ensure that, once the roof is lowered, the dormer is also lowered and beneath the original ridge line and that it complies with the provisions of Schedule 2, Part 1, Class B of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended).