using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var inputs = new List<string>();

        inputs.Add("13A House Street");

        inputs.Add("869      ");

        inputs.Add("101      Folkestone Court");

        inputs.Add("A House Street");

        inputs.Add("Test my address 123");

        foreach (var input in inputs)

        {

            var houseNumber = new string (input.TakeWhile(char.IsDigit).ToArray());

            var houseName = string.Empty;

            if (houseNumber.Length > 0)

            {

                houseName = input.Substring(houseNumber.Length).Trim();

            }

            else

            {

                houseName = input.Trim();

            }

​

            var subHouseNumber = new string (houseName.TakeWhile(char.IsLetter).ToArray());

            if (subHouseNumber.Length == 1 && houseNumber.Length > 0)

            {

                houseNumber += subHouseNumber;

                houseName = houseName.Substring(subHouseNumber.Length).Trim();

            }

​

            Console.WriteLine($"HouseNumber = '{houseNumber}'");

            Console.WriteLine($"HouseName = '{houseName}'");

            Console.WriteLine("-----------------------------------------------");

        }

    }

}