Durrell, 32, returned to the Bucks in the summer after a number of successful spells at clubs in non-league, and was a regular starter under Gavin Cowan and interim manager Dennis Greene.
But last month new manager Paul Carden revealed Durrell was not in his plans, and he needed "everyone pulling in the same direction."
Durrell hasn't been involved in any of the recent Bucks matchday squads and on social media on Thursday evening, the club confirmed it had agreed a permanent transfer for the playmaker with an unnamed club.
Hours later Northern Premier League side club Grantham Town, now managed by ex Bucks man Greene, revealed that Durrell had put pen to paper on a deal for them.
And in the same evening, the club also confirmed former EFL midfielder Kyle Bennett had left the club.
In a statement, the club said: "We would like to wish Kyle all the very best in the future and thank him for all his efforts during his spell at the club especially during difficult circumstances for him."