Looks like we screwed up on the roof and the required red tape. Apparently work finally commenced yesterday, they had taken off half of the rear when M. le Maire turned up and put a stop to work because we don't have the required permits.
Having been to the Mairie and spoken with the secretary and with various builders we were under the impression that no permission was required just to renovate the roof, but permission is required for the windows (as these will be changes to the exterior) and we have submitted the necessary demande de permis de construire for those.
However, we were all under the impression that we could commence work on the renovation as long as the windows did not appear until we have the permis. As the windows will be the final component of the work, we were hoping that the permis would be in place at that point. The roofer was under the same impression. But apparently not in our village!! This Maire is newly elected so don't know if he just wants to make himself visible (!) - whatever we have emailed the Maire to find out where we go from here. It is upsetting as the roofer and his team have obviously committed themselves to our job and now cannot proceed PLUS we have no rear roof now.
I know for sure where I live we don't require permission to replace our roof!!