 On 1 December 2009, Thelwell left Newport and joined Kettering Town on a free transfer, but retired after nine games through injury.Thelwell returned to football and joined Carshalton Athletic in the autumn of 2012 on a non-contract basis as the club was suffering from a defensive crisis.He made ten appearances for The Robins before moving on to Billericay Town, who were then playing in the Conference South.