Why not use a postcode database from an official source, such as Ordnance Survey's CodePoint Open - ordnancesurvey.co.uk/oswebsite/products/code-point-open - which is also free, and updated four times a year.
CodePoint Open doesn't include the 'specials', because they're not geographically tide (so the valid "SAN TA1" postcode isn't included), but do you really expect to be delivering to the headquarters of the FA or any of those "own postcode" organisations? If you do need those, then you can always add them manually.