Bush, who recently turned 24, has plenty of experience in non-League football having had spells at Welling United, Hereford nited, Gateshead and Woking.
The 6`3” centre-half was an important member of the Imps squad last season, making thirty-six appearances in total – thirty-four of which were starts - and scored one goal.
The London-born defender also has Football League experience from his time with AFC Wimbledon, playing twenty-seven times in their maiden Football League campaign in 2011/12 following their re-formation.