ref_regex.py

import re
import sys
from datetime import datetime

p = re.compile('([A-Za-z][0-9]{4}[A-Za-z]{2}).*?([0-9]{1,2}).*?([0-9]{1,2}).*?([0-9]{2,4})')

def parse_ref(ref):
    m = p.match(ref)

    if m:
        date_str = '%s/%s/%s' % (m.group(2), m.group(3), m.group(4))
        try:
            dob = datetime.strptime(date_str, '%d/%m/%Y')
        except ValueError:
            dob = datetime.strptime(date_str, '%d/%m/%y')

            # set correct century for 2 digit year
            if dob.year > datetime.today().year - 10:
                dob = dob.replace(year=dob.year-100)

        print('%s, %s' % (m.group(1), dob.strftime('%Y-%m-%d')))

parse_ref('a1450ae20071976')
parse_ref('A1450AE20/07/1976')
parse_ref('A1450AE 01-07-76')
parse_ref('A1450AE 1776')
parse_ref('A1450AE:01 07 76')

if len(sys.argv) > 1:
    parse_ref(sys.argv[1])