The experienced defender, who is comfortable at either full back or centre back, made 500 appearances for Football League clubs in a 14 year professional career. Terrell started with West Ham, progressing through their youth system and featured in their 1999 FA Youth Cup win alongside the likes of Michael Carrick, Joe Cole and Stephen Bywater. After leaving the Hammers, Terrell enjoyed three years at QPR, racking up 114 appearances and winning promotion in 2004.

That summer he departed for Grimsby and a year later moved up a division to join Oldham Athletic. He then settled at Yeovil from 2006 to 2010, playing 163 games. Terrell joined Leyton Orient in May 2010, he scored two goals during 73 appearances in two seasons for Orient. Chesterfield signed Terrell in 2012 and after making 17 appearances he moved to Aldershot Town. However, the Hampshire club went into Administration, forcing them to release their entire playing squad in May 2013. Dover moved to sign Forbes to add valuable experience to their young squad.

After one season he moved on to Dulwich Hamlet, where he featured regularly in a defence with the Isthmian Leagues second best defensive record as Hamlet reached the semi-finals of the Play Offs. Terrell joined The Tudors in the summer of 2015.