Mark Webster is set to return to the Sky Sports commentary box on Thursday following a positive update on his battle with cancer. The 2008 British Darts Organisation (BDO) World Championship winner has been absent from the commentary box since starting chemotherapy in February after being diagnosed with rare form of blood cancer known as hairy cell leukaemia. Just last week, the 42-year-old Welshman had publicly shared that his recovery was "not going to plan in terms of the speed of it." However, in a welcome turn of events, he announced on Tuesday that he has been cleared to rejoin the broadcast team for Thursday night’s Premier League event in Birmingham.…