Yes. In most of Arlesey, extending or altering a house means dealing with ordinary planning rules, and heritage rules rarely come into it. The town has only a few listed buildings. It has no conservation area. Neighbours are applying for planning permission at a steady rate. The main complication is the ground, which is clay that swells and shrinks.
Arlesey has eight listed buildings: one at Grade I, none at Grade II*, and seven at Grade II. Listing protects a building's interior as well as its exterior, so changing a window, a wall or a fireplace in one of those eight needs listed building consent on top of any planning permission. For everything else in town that layer does not apply, and there is no conservation area to add a second one. Arlesey's best-known product, the Arlesey White brick, went out to build other places and is protected far more there than at home.
Central Bedfordshire Council recorded 129 planning applications in Arlesey between April 2024 and June 2026, and 67 of them came in the last twelve months. Those numbers show people adding, converting and rebuilding in a town of about 2,500 households, and a buyer planning a rear extension will be in good company.
The ground is the part that needs more thought. The British Geological Survey rates every postcode in Arlesey at class 3 for shrink-swell, which means clay that expands when wet and shrinks when dry. The town spent generations digging Gault clay out of the ground to fire into bricks, and the same kind of ground is still under the houses. In practice, an extension here usually needs deeper foundations designed for clay, and a structural engineer should be involved early, especially where there are large trees nearby, since tree roots draw water out of clay. The building is still possible, but the foundation work costs more.
Outside a conservation area and away from the listed buildings, many modest rear extensions, loft conversions and outbuildings can go ahead under permitted development. These are the national rights that let householders build within set size limits without a full planning application. Larger or more prominent projects go through Central Bedfordshire's normal planning process. Some newer estates have had their permitted development rights removed by planning condition, so it is worth asking the council whether the house being considered is one of them. That one check can turn a simple loft conversion into a full planning application.
Freedom to extend is one of Arlesey's strengths. The planning rules leave owners plenty of room, and the clay ground is the main thing that pushes the cost up.