Career
He previously played for Moseley, Penzance-Newlyn, and for Redruth whom he joined from Gloucester Rugby. He played regularly for the England Sevens team Saracens
Educated at Richard Lander School, Thirlby began his career with Redruth before guesting for Penzance & Newlyn in the 1998 Safari Sevens tournament in Kenya where he was spotted by Kyran Bracken who recommended him to Saracens and Thirlby joined the club ahead of the 1998-1999 season.
He made his Sarries debut in an Anglo-Welsh clash with Cardiff on 16 January 1999, kicking 11 points in a 36-22 victory.
He made his Premiership debut against Northampton Saints on 6 February 1999 and went on to make 28 appearances for the club in the competition, scoring six tries. Bath Rugby
Thirlby left Saracens to join Bath Rugby in May 2000 and celebrated his move with a call up for England"s 2000 tour of South Africa.
Although he did not appear in the test side, he played in the three tour matches, scoring a try in the 36-27 victory over Gauteng Falcons. He played 36 times for Bath in the Premiership scoring eight tries, the highlight being the hat-trick of tries he scored against Rotherham on 14 April 2001, before joining Rotherham in February 2003.
He helped the club secure promotion from National Division One back into the Premiership before returning to Cornwall and Penzance & Newlyn for the 2003-2004 season.
Gloucester Rugby
After two seasons with Penzance & Newlyn, Thirlby returned to the Premiership by signing a two-year contract with Gloucester Rugby. After just ten Premiership appearances and a solitary try, Thirlby joined Redruth on loan in January 2007, agreeing a permanent two-year contract with the club in March 2007. England Sevens
He has made 35 appearances in the Institutional Review Board Sevens World Series, the third highest total by an England player.