Yes. For most houses in Ascot, an extension is an ordinary planning matter and nothing more. Only a few dozen buildings are listed. There's one conservation area, at Winkfield Row. Hundreds of planning applications go in every year. Ascot's heritage rules are light, but the planning department is busy.
The area has 71 listed buildings. One is Grade I, two are Grade II* and 68 are Grade II. Listing covers the whole building, inside and out, so almost any change that affects its character needs listed building consent on top of planning permission, and that includes new windows, internal walls and extensions. Grade I and II* buildings get the closest scrutiny, but Grade II is still a legal designation. If you're viewing one of those 68 houses, find out what the council will let you change before you start choosing kitchen units.
There's one conservation area, Winkfield Row. In a conservation area, demolition, work to trees and some changes the rules would allow elsewhere can need the council's permission. Outside Winkfield Row, conservation rules don't touch most of Ascot.
The area also has 3 scheduled monuments, the strictest tier of heritage protection. They matter mainly if your land is next to one.
Between April 2024 and June 2026, Ascot received 1,292 planning applications, and 533 of them came in the twelve months to June 2026. That shows people here alter their homes regularly. Whatever you have in mind, the council has probably seen something like it on a neighbouring plot.
For an ordinary house that isn't listed and isn't in Winkfield Row, many smaller extensions and alterations can go ahead under permitted development, the national rules that let you build within set limits without a full application. Anything larger, anything on a listed building, and most work inside the conservation area needs consent. Some houses have had their permitted development rights removed by conditions on earlier permissions. Before you offer, ask the council for the planning history of the exact address and check whether those rights are still in place.
Your freedom to extend in Ascot is middling. The heritage rules are light for most houses, but listed buildings and Winkfield Row carry real restrictions, and the planning department is busy enough that you should expect a full process for anything sizeable.