Purches is a defender who can play at centre back, midfield or full back on either side. He was previously a trainee at West Ham United but left in 2000 after failing to make a single appearance for the first team. He joined Bournemouth where he spent seven years and missed only three league games in his time at the club.
In summer 2007, he rejected a new contract at Bournemouth and left on a free transfer to join Leyton Orient. Purches watched his first football matches at Orient and described his move as being "like coming home". He was also handed the team captaincy when he arrived. After 132 games in all competitions, he was released by manager Russell Slade on 9 May 2010. On 7 June 2010, Purches re-signed for Bournemouth. On 18 February 2012, Purches broke his leg playing in a match against Rochdale.