Some regex to clean OCR 'O' for zero mistakes in UK postcodes

OcrPostcodeCleaningEx.cs

using System.Text.RegularExpressions;

foreach (var postcode in args)
    Console.WriteLine(postcode.ReplaceAnyMisplacedO());

static class OcrPostCodeCleaningExtensions
{
    public static string ReplaceAnyMisplacedO(this string postcode) =>
        postcode.ReplaceAnyFrontO().ReplaceAnyEndO();

    private static string ReplaceAnyFrontO(this string postcode) =>
        Regex.Replace(postcode, @"^(?<start>[A-Z]{1,2}[0-9])O(?<end>\s?(O|[0-9])[A-Z]{2})$", "${start}0${end}");

    private static string ReplaceAnyEndO(this string postcode) =>
        Regex.Replace(postcode, @"^(?<start>[A-Z]{1,2}[0-9]{1,2})\s?O(?<end>[A-Z]{2})$", "${start} 0${end}");
}