After making several appearances, Sitton fell out of favour with then-manager Geoff Hurst,[6] and, after turning down an approach from Wimbledon, transferred to Fourth Division Millwall for £10,000 in February 1980 under George Petchey.

Sitton enjoyed his time at Millwall but new manager Peter Anderson took an instant dislike to Sitton and sold him to Third Division side Gillingham in September 1981 and spent four seasons there under manager Keith Peacock before being signed by Frank Clark for Fourth Division side Leyton Orient on a free transfer in July 1985 where he was made club captain.

[7] After his release in May 1991, he started working for Orient's School of Excellence Academy as a youth coach whilst making a few appearances for Slough Town in the Conference.

Sitton was appointed joint caretaker manager at Leyton Orient with Chris Turner in August 1994, following the departure of Peter Eustace, and helped the team avoid relegation from the Second Division by earning four points from their last two matches.

The co-managership was Sitton's idea, as he did not know many of the first team players since he moved into coaching in Orient's youth setup, and knew that Turner had more knowledge about them.

The duo were given the job permanently that summer after the board received positive feedback from the players, and continued throughout the difficult 1994–95 season in which Sitton had to work in six different roles within the club whilst on a youth coach salary.

Sitton also worked at the Press Association, compiling statistics for Arsenal matches for the Actim Index, and had also spent some time as a martial arts instructor.

From 2012 to 2014 Sitton did several interviews with television producer Vernon Grant on YouTube[11] in which he discussed his playing career and his time as Leyton Orient manager.

Sitton related his hopes of creating a Wimbledon-style Crazy Gang mentality at Leyton Orient, coupled with youth development along the lines of Dario Gradi's work at Crewe Alexandra.

The book was delayed numerous times throughout 2013 and 2014, only for the collaboration to dissolve acrimoniously in October 2014, which effectively cancelled the biography just weeks before it was supposed to be released.