If the above procedures do not separate the Clubs, then the Clubs concerned shall play off a deciding League Match or Matches under arrangements approved by the Board on a neutral ground.
Taken from the official Football league site:
9.2 If two or more Clubs have the same number of points, goal difference and goals scored the highest placed Club shall be determined by the respective League records against each other, taking into account in order of precedence, points gained, goal...