In most of Pembury, yes, and the neighbours are already doing it. Only a handful of homes are listed. There's no conservation area. A slice of the village sits in protected countryside. Planning applications arrive at a rate of more than one a day. Scaffolding might as well be Pembury's official public art.
Historic England lists 67 buildings in Pembury: one at Grade I, two at Grade II* and 64 at Grade II. Listing covers the whole building, inside and out, so any change that affects its character needs listed building consent on top of any planning permission, and work carried out without it is a criminal offence rather than a paperwork slip. If the house you're after is one of those 67, budget for a heritage specialist, a longer timeline and some firm opinions about your window frames. If it isn't, and in a village this size most homes aren't, listing won't slow you down.
The local planning register holds 1,256 applications for Pembury between April 2024 and June 2026, with 570 in the last twelve months alone. That's people submitting plans for rear extensions, loft conversions and garden rooms, on a scale that suggests half the village is measuring up the side return. It says nothing about how many were approved, only that asking is normal here. Nobody's going to treat you as the difficult neighbour for submitting one.
In practice, most houses outside the listed stock can use permitted development rights. These allow some rear extensions, loft work and outbuildings without a full planning application, within national size limits. With no conservation area in the village, that freedom mostly survives. The exception is the roughly 11% of the area inside the High Weald Area of Outstanding Natural Beauty, where some permitted development rights are reduced and more work needs a proper application. Before relying on a builder's reassurance, check whether the house has had its rights removed by an earlier condition, and ask the council for a lawful development certificate if there's any doubt. It costs far less than knocking down an extension you built without the right paperwork.
Pembury is a middling place for extending: open for most houses, restrictive for the listed ones, with a strip of protected countryside where you'll need permission first. Buy the ordinary semi and you can add your extension. Buy the listed cottage and you're mostly its caretaker.