Hoping someone can advise, I live in a house that is exactly the same as the ones identified in the links;
http://www.npt.gov.uk/PDF/permitted_development_for_householders_technical_guidance.pdf (fig2 page 5)
http://www.pkc.gov.uk/CHttpHandler.ashx?id=21718&p=0 (fig2 page 9)
We had a loft...