Sandeman started his career at Northampton Town under the management of Graham Carr in 1986. The "Cobblers" avoided relegation out of the Third Division in 1988–89 only due to their superior goal difference to Southend United. They failed to avoid the drop into the Fourth Division in 1989–90, which led to Carr being sacked and replaced by Theo Foley. Sandeman left the County Ground in February 1991, having been sold on to league rivals Maidstone United for a £10,000 fee; the move reunited him with former boss Graham Carr. The "Stones" finished in the lower half of the table in both 1990–91 and 1991–92. He left the club just months before its collapse.
Port Vale
He joined Port Vale in July 1992, with manager John Rudge looking to add strength in depth to help with the push for promotion out of the Second Division. He was a regular first team player in 1992–93 until he picked up a thigh injury in February, which required an operation. This caused him to miss both the 1993 League Trophy Final and the 1993 Second Division play-off Final at Wembley. He was used sparingly following his recovery, leaving him to play a limited role in the 1993–94 promotion campaign until he re-gained his first team spot in May 1994. He was a first team regular in the First Division in 1994–95, before he fell out of favour once again in July 1995. The 1995–96 season was his last at Vale Park, and was not picked to play in the final of the Anglo-Italian Cup. He was given a free transfer to Rotherham United in May 1996.
Rotherham United
Originally signed to play at right-back, he soon was pushed further forward into midfield. The "Millers" suffered relegation out of the Second Division in 1996–97 under Danny Bergara, though Sandeman had left the Don Valley Stadium for Hereford United in March 1997.
Later career
He made just seven appearances for the "Bulls", and left the club in the summer after the Edgar Street club were relegated into the Conference under Graham Turner. He spent the first half of the 1997–98 season with Northwich Victoria, before joining Conference rivals Kettering Town, who were managed by former teammate Steve Berry. He later combined his duties as a postal worker with playing semi-professional football. He signed with Leek Town in July 2000 and scored seven goals in 55 appearances in the 2000–01 season as the "Blues" were relegated out of the Northern Premier League Premier Division; he was voted as the club's Player of the Season. He then moved on to Hyde United, but did not make an appearance for the "Tigers". He served Witton Albion as caretaker-manager in August 2003 winning all four matches. He joined Kidsgrove Athletic in July 2004. He signed with Dover Athletic in February 2005 after being recruited by Clive Walker.
