Permitted Development and hip to gable loft conversions

My Architect recently achieved Planning Permission for a rear extension and Certificate of Lawfulness of Permitted Development for a large loft conversion on a semi-detached Victorian house in Islington. Guidance from the duty planner was that a hip to gable conversion would NOT be considered permitted development (PD) and that these works would also not be granted planning permission if submitted for planning. Our research into PD guidelines and recent precedent showed that this advice was misleading, and that a hip to gable conversion, if carefully designed, would constitute PD. By providing precedent from the Planning Inspectorate we were able to demonstrate that the works DID constitute PD and succeeded in achieving the appropriate approvals.