Posh rallied before the interval but Aaron McLean shot wide from 20 yards and Tommy Rowe had a shot blocked after another long Geohaghon throw-in caused chaos.
Whilst Glenn Walker has been offered a new contract, the club did not give deals to Aaron Butcher, Liam Dolman, Jordan Fitzpatrick, Tommy Jaszczun, Tom Manship, Scott Mooney or Netan Sansara.