Probably, and probably not in the way you first pictured it. This is one of the most heavily protected corners of Devon, with hundreds of listed buildings, five conservation areas and a scattering of scheduled monuments across the surrounding parishes. People here do extend, alter and convert, in decent numbers, every year. What they do not do is any of it quickly, or without a conversation. The building comes with an opinion of its own, and the opinion is legally enforceable.
The listing picture is the first thing to establish. Historic England's register carries 492 listed buildings across this area: 11 at Grade One, 22 at Grade Two Star and 459 at Grade Two. Listing applies to the whole building inside and out, and usually to anything attached or within its curtilage, which is where owners get caught out. Replacing windows, altering internal walls, changing a roof covering, adding a flue, even swapping the front door can all require listed building consent, and doing the work without it is a criminal offence rather than a paperwork problem. Grade Two is the ordinary case here by a wide margin, and it is not the light-touch tier that some buyers assume.
There are five conservation areas across the wider area, covering Chulmleigh itself along with Winkleigh, Burrington, Ashreigney and Broadwood-kelly. Conservation area status works on the outside of a building rather than the inside: it brings control over demolition, tighter rules on what can be done to the street-facing elevation, and protection for trees, so lopping something in the front garden becomes a notifiable act. Permitted development rights are commonly restricted inside these boundaries, and Mid Devon District Council is the authority that decides where those restrictions bite. The boundary lines matter enormously and follow no logic a buyer can guess from a map: two houses of the same age on the same road can sit on opposite sides of one.
There are also 20 scheduled monuments in the area, which is the strictest protection tier in the system. These are archaeological sites rather than homes, mostly barrows, crosses, castle earthworks and hillforts across the surrounding farmland, and they matter to a householder only when the land in question sits on or beside one. If it does, the consent regime is national rather than local and is not negotiable.
None of which stops the work happening. Mid Devon's planning register carries 138 applications across this area between April 2024 and June 2026, with 69 of those in the most recent twelve months. That is a steady stream of people getting extensions, conversions, outbuildings and alterations through the system rather than an area where nobody bothers trying. The pipeline is real and it is current.
Practically, that leaves two very different experiences depending on which house you buy. Outside the conservation areas and off the register, a bungalow or a post-war house here has the ordinary permitted development rights, generous plots and neighbours far enough away to make an objection less likely, which is about as easy as extending gets in England. Inside the protected footprint, assume nothing is permitted development until Mid Devon District Council confirms it in writing, and budget for a conservation officer's view on materials before an architect draws anything.
Freedom to alter a home is the weakest thing this area offers, and it is weak precisely because of what makes the place attractive to look at. Check the listing entry and the conservation area boundary for the specific address before you fall for the house, because the survey will tell you what the building is, and only the register will tell you what you are allowed to do to it.