 McAllister was loaned to National League South club Eastbourne Borough in September 2016 on a one-month loan.He debuted in a 4–0 victory at home to Oxford City on 3 September 2016 and completed the loan spell with one goal from five appearances.McAllister made his first appearance of 2016–17 for Sutton on 4 October in a 3–1 defeat away to Dover Athletic and scored his first goal in the following match, a 4–1 victory at home to former club Woking, in which he scored a header to make the score 4–0.