Later career
Following a disagreement with Cash, Aherne moved to Australia and retreated from the press. She wrote Dossa and Joe which was screened on BBC Two in 2002. Although critics applauded it, the show failed to attract viewers and did not return for a second series. Returning to Britain, she began work on another sitcom with Cash, but pulled out, after which Cash wrote Early Doors with Phil Mealey; Aherne was listed in the credits in the "Thanks To" section.
After Dossa and Joe, Aherne avoided media attention. When The Fast Show was featured on the BBC One show Comedy Connections, Aherne was the only cast member not interviewed. In April 2006, the BBC said Aherne and Cash were developing a script for a one-off special of The Royle Family. The Royle Family: The Queen of Sheba was broadcast on 29 October 2006, to an audience of 7.8 million. Aherne subsequently made few TV appearances. On 14 October 2008, she appeared in the BBC comedy drama Sunshine, written by Cash and Phil Mealey, as a barmaid. She appeared in The Royle Family special "The New Sofa" on Christmas Day 2008. In 2009, she appeared in another special for Comic Relief, as well as another Christmas Day special entitled "The Golden Eggcup".
She co-wrote the ITV comedy-drama The Fattest Man in Britain, which was broadcast in December 2009. In November 2010, Aherne appeared in the special The Royle Family: Behind the Sofa shown on Gold, featuring clips of The Royle Family and interviews with Aherne, Cash and the cast, which was followed by another Christmas Day special, "Joe's Crackers". She narrated a BBC1 documentary series Pound Shop Wars broadcast in November 2012. She also appeared in The Fast Show internet specials, sponsored by the lager brand Fosters, which reunited most of the original principal cast; only Mark Williams was unable to participate.
Aherne wrote the 2013 one-off sitcom The Security Men, along with Jeff Pope for ITV. The episode starred Paddy McGuinness, Brendan O'Carroll, Dean Andrews, Bobby Ball and Peter Wight.
Aherne's final major role was as narrator of the Channel 4 comedy reality series Gogglebox, reflecting her character in The Royle Family, who would frequently be watching TV and commenting on it. Cash filled in when she was unavailable and took over the role permanently in April 2016.
Aherne's final on-screen appearance came in the Sky One show After Hours, where she was reunited with Cash who produced and directed the show. She played the role of Sheila.