I recently added insulation to the external roof plane of my roof because i thought it was within permitted development rights but received an enforcement notice on it from my council. They said that I altered the plane and slope which is the same as an extension.... I want to appeal it on grounds that it is a development similar to adding a velux rooflight ie less than 150mm from the rooflsope.
To do so, I am looking for examples where the external plane of the roofslope has been altered under permitted development rights so that insulation can be added as long is it does not protrude more than 150mm from the plane of the roof.