Heydon joined the PDC in 2010, and quickly made an impact, reaching a semi-final in his second Pro Tour event in Gibraltar.
[2] In August, Heydon beat Brandon Walsh and Gary Butcher in the UK Qualifier for the European Tour Event 4,[3] and defeated Andy Smith 6–5 in the first round in Stuttgart.
[6] Heydon's best results of 2012 came after this as he reached the quarter-finals of both the 12th and 16th Players Championship events, losing to Andy Hamilton (5–6) and Jamie Caven (0–6) respectively.
[11][12] He started 2014 ranked world number 71, outside of the top 64 who retained their places on the tour and Heydon therefore entered Q School in a bid to win his spot back.
[15] In February 2014, Heydon enjoyed his best run in an event in 16 months by reaching the last 16 of the fifth UK Open Qualifier with victories over the likes of Mark Walsh and Richie Burnett, but lost 6–3 to eventual winner Gary Anderson.
[17] His form continued at the third Players Championship as he reached the semi-finals of a PDC event for the second time in his career by whitewashing John Part and also beating Ian White and Ronnie Baxter, before Phil Taylor defeated Heydon 6–0.
[21] The highlight of Heydon's year undoubtedly came at the 11th Players Championship event in May, when he overcame Darren Johnson, Alan Norris, Mark Dudbridge, John Bowles and Jelle Klaasen to play in the semi-finals, where he lost 6–4 to Dave Chisnall.
[23] In 2016, he qualified for the Austrian Darts Open, where he made the quarter-finals by beating Roxy-James Rodriguez 6–4, reigning World Grand Prix champion Robert Thornton 6–5 and number six seed Ian White 6–0.