Once a house has a number you will generally not be allowed to change it.
Here is some advice from Savills solicitors:
House names can be very personal, and not everyone wants to live in ‘Dunroamin’ or ‘Nirvana’. The procedure for changing a name is well established, if a little bureaucratic.
There are rules - you will not be allowed a new name that could conflict or cause confusion with another house in the locality. If you have a house number, then it is more restrictive. Numbers cannot be changed or deleted, although you may add a name to the existing street number without getting permission.
To change a house name you need to apply to your local council, who might charge an administration fee. The council will consult with Royal Mail to ensure there is no conflict, and once approved will provide a certificate of renaming and inform the Royal Mail, Land Registry, Electoral Registration, Council Tax and Planning Department.
You should also contact the Royal Mail to make sure their records are updated, and inform your utility companies, mortgage company, and emergency services including Doctor, as it can take up to 12 weeks for the various agencies to update their records.