The proposed bedroom annexe, by virtue of its scale, massing, orientation and proximity to the boundary with 68 Canterbury Park, will represent an overdominant feature that will unduly impact on the amenity of the occupiers of that property by reason of overdominance and overshadowing of their amenity area. As such, the proposal is contrary to Saved Policy HD18 in the Liverpool Unitary Development Plan and one of the core planning principles of the National Planning Policy Framework