Yes, and the planners are the easy part. No conservation area covers the town. The listed buildings are few and all at the ordinary grade. The neighbours file applications all the time. The ground under the lawn will ask harder questions than the council.
Ashley has 14 listed buildings, and every one of them is Grade II: none at Grade I, none at Grade II*. Listing means listed building consent for almost any change inside or out, from windows to walls, and the odds of owning one of those 14 are slim in a town built mostly after the war. For everyone else, the heritage file is thin. There are no conservation areas and no scheduled monuments inside the area, so the tighter rules that come with those don't reach your extension.
The neighbours are already busy. Planning records show 1,660 applications between April 2024 and July 2026, with 686 in the most recent twelve months. That doesn't tell anyone how many were approved. It does show that altering a house here is normal behaviour rather than a brave act, and anyone told locally that "they never let you do anything" is hearing a story, not a statistic.
The real constraint is underground. The British Geological Survey places Ashley at class 3 for shrink-swell, and 100% of its postcodes reach that class. Shrink-swell ground is clay that expands when wet and contracts when dry, and it moves foundations with the seasons. For an extension, that means deeper footings than a builder's first quote might assume, and a structural engineer's view before anything is dug, especially near trees. It is a published hazard class, not a reason to panic, but it is a line on the invoice. Buyers who budget for the kitchen and forget the concrete underneath find out about clay the expensive way.
In practice, most modest rear extensions, loft conversions and outbuildings on an ordinary house here are likely to fall under permitted development, the national rights that let many changes go ahead without a full planning application, because the area has no conservation-area overlay to strip those rights away. Anything larger, anything on a listed building, or anything the permitted rules don't cover needs consent from the council. The sensible order is to check the house's own planning history and any conditions on it first, ask the council whether a lawful development certificate is worth having, and only then brief an architect.
Freedom to extend is one of Ashley's better points. The planning rules are ordinary, the heritage constraints are rare, and the clay, not the council, is what sets the budget.