Yes, and with less paperwork than most of Cornwall's coastal villages demand. The whole place contains one listed building. There is no conservation area. There is no scheduled monument. Downderry is shaped by its geography rather than by designation, and geography does not run a planning department.
The listed-buildings register carries exactly one entry for this area, graded two, with none at grade one and none at grade two star. For that single property, listing is a serious constraint: consent is needed for alterations affecting its character, inside as well as out, and the feature you most want to change is usually the feature the conversation ends up being about. For every other home here, it is a piece of local trivia rather than a restriction. No conservation area boundary runs through the village, and no scheduled monument sits inside it, so the extra layers of control that catch owners in more heavily branded villages along this coast are simply not present.
The neighbours are not sitting on their hands. The planning register recorded 234 applications across this area between April 2024 and June 2026, of which 95 fell in the most recent twelve months of that window. That is a steady stream of loft conversions, garden rooms, replacement glazing and rebuilds being put in front of the council by people who live here. Whatever else this village is, it is not one where nobody bothers applying.
In practice, the ordinary things owners want to do to a detached house or a bungalow tend to fall within permitted development, which means no full application is needed provided the work stays inside the national limits on size, height and position. Those rights are not universal. They do not apply to the listed property at all, they do not extend to flats, and a council can remove them from specific areas or properties. The five-minute version of due diligence is to ask the council whether permitted development rights still apply to the particular address before an architect starts drawing, rather than after.
Freedom to alter a home is one of the genuinely easy things about buying here, with a heritage footprint of a single listed building and no designation covering anyone else. If something stops your extension in Downderry, it will be the site, the survey or the budget doing it.