Maybe... JST XH 2.54 6 pin female

[![JST XH 2.54 6 pin female][1]][1]

and the reverse side, showing the locking, with the male PCB connector

[![JST XH 2.54 6 pin female - reverse side with locking mechanism][2]][2]


  [1]: https://i.sstatic.net/ECbqm.png "JST XH 2.54 6 pin female"
  [2]: https://i.sstatic.net/vSZYE.jpg "JST XH 2.54 6 pin female - reverse side with locking mechanism"