GB Postcodes validation and formatting

GBPostcodeUtil.cs

using System;
using System.Text.RegularExpressions;

namespace MyCommons
{
    public static class GBPostcodeUtil
    {
        // Used regular expression from the article: http://www.qwghlm.co.uk/blog/?p=761
        // Original pattern:
        public const string FORMATTED_MATCHPATTERN = "^[A-PR-UWYZ][A-HK-Y0-9][A-HJKSTUW0-9]?[ABEHMNPRVWXY0-9]? {1}[0-9][ABD-HJLN-UW-Z]{2}$";

        // Modified for user flexibile input:
        // 1. Lower case 
        // 2. Spaces 
        private const string PATTERN_BEGIN = "[A-PR-UWYZa-pr-uwyz][A-HK-Ya-hk-y0-9][A-HJKSTUWa-hjkstuw0-9]?[ABEHMNPRVWXYabehmnprvwxy0-9]?";
        private const string PATTERN_END = "[0-9][ABD-HJLN-UW-Zabd-hjln-uw-z]{2}";
        public const string MATCHPATTERN = "^ *" + PATTERN_BEGIN + " *" + PATTERN_END + " *$";

        public static bool IsPostcodeValid(string postcode)
        {
            return IsPostcodeValid(postcode.Trim().ToUpper().Replace(" ", ""), MATCHPATTERN);
        }

        private static bool IsPostcodeValid(string postcode, string pattern)
        {
            try
            {
                var match = Regex.Match(postcode, pattern);
                return (match.Success && (match.Index == 0)) && (match.Length == postcode.Length);
            }
            catch
            {
                // Something happened. We cant allow parse this postcode as we are not sure if it is valid.
                return false;
            }
        }

        public static string GetPostcodeWellFormatted(string postcode)
        {
            if (!IsPostcodeValid(postcode))
                throw new FormatException("Invalid postcode: " + postcode);

            postcode = postcode.Trim().ToUpper().Replace(" ", "");

            var endMatch = Regex.Match(postcode, PATTERN_END + "$");

            if (!endMatch.Success || endMatch.Groups.Count == 0)
                throw new FormatException("Invalid postcode: " + postcode);

            var endString = endMatch.Groups[0].Value;

            postcode = postcode.Remove(postcode.Length - endString.Length);
            postcode = String.Format("{0} {1}", postcode, endString);

            if (!IsPostcodeValid(postcode, FORMATTED_MATCHPATTERN))
                throw new FormatException("Invalid postcode: " + postcode);

            return postcode;
        }
    }
}