Yes, in most of Liphook, and the ground is more of an obstacle than the heritage rules. Listed buildings are few. There's a single conservation area, around the old centre. Neighbours are putting in planning applications all year. The heritage rules cover only a small part of the village. The clay soil is everywhere.
Historic England lists 17 buildings in the area. None is Grade I. One is Grade II* and the other 16 are Grade II. Listing covers the inside of a building as well as the outside, so almost any alteration to a listed home needs listed building consent on top of any planning permission, from the windows to the staircase. With 17 listed buildings in a village of this size, the odds are you aren't buying one. If you are, the consent process becomes part of every job, not a one-off before the builders start.
There's one conservation area, and it takes the village's name: Liphook, covering the historic centre. Inside it, the council takes a closer interest in anything visible from the street, and some extensions that would go ahead without permission elsewhere need an application. Anything in or near the old centre should be treated as needing consent until the council confirms it doesn't. The post-war estates that make up most of the village sit outside it.
There's also one scheduled monument in the area, the strictest tier of heritage protection. It matters mainly if your land runs up to it, and most back gardens won't.
People in Liphook do extend and alter their homes, and often. The local planning register recorded 387 applications between March 2024 and June 2026, including 183 in the most recent twelve months. That count is volume only. It says nothing about how many were approved, so treat it as evidence that people try, not proof that they succeed. An estate agent's "scope to extend, subject to planning" is exactly that, subject to planning, and the listing photos won't tell you which way the decision would go.
The ground is the part the estate agent's brochure won't mention. The British Geological Survey puts all of Liphook in shrink-swell class 3 or above, the band where clay swells when wet and shrinks when dry enough to move foundations. That doesn't stop anyone extending. It means extensions usually need deeper foundations than builders would put in on stable ground, and a structural engineer should be involved before an architect finalises the drawings. Nearby trees and drains make the effect worse, so they're worth checking too.
In practice, a house on a post-war estate outside the conservation area and not listed will often fall under permitted development for modest rear extensions and loft conversions, with the usual limits on size and position. A house in the old centre, or a listed one, should be treated as needing full consent for most changes. Either way, check the council's planning register for your street before you buy. What the neighbours have already been refused is the most useful precedent you'll find.
Your freedom to extend in Liphook is middling. The heritage restrictions affect only a small part of the village, but the clay under all of it means any extension needs deeper foundations and an engineer's input.