If your home is a listed building, it has been rated of national importance in terms historic or architectural interest. Listed buildings feature on a register called the List of Buildings of Special Architectural or Historic Interest https://historicengland.org.uk/listing/the-list/ . The rules around listed buildings, mean that any garden building or outbuilding that is to be placed within the curtilage of a listed building will require planning permission.
There are additional matters to consider if your home is located on designated land, eg. national parks, the Broads, World Heritage Sites, Areas of Outstanding Natural Beauty and conservation areas. If your home is within a national park, World Heritage Site, the Broads or an Area of Outstanding Natural Beauty then you need to obtain planning permission unless the garden building is less than 10m2 and at least 20m away from any wall of your home. If your home is within a national park, World Heritage Site, the Broads, an Area of Outstanding Natural Beauty or a conservation area, then you may not construct a garden room to the side of your home without obtaining planning permission.