MAYO
* By-election triggered by May resignation of Centre Alliance's Rebeckha Sharkie over her dual British citizenship.
* Held by Sharkie with a five per cent margin.
* Mayo takes in the Adelaide Hills through to Kangaroo Island.
* Sharkie is expected to retain the seat, but faces a challenge from the Liberals' Georgina Downer, the daughter of former federal minister Alexander Downer.
* If elected Downer will be the fourth generation of her family to serve in federal parliament.
* Seven candidates have nominated, including Labor's Reg Coutts.
* GetUp has run a public campaign linking Downer to cuts to the ABC. The Liberals have countered saying voting for Sharkie is the same as voting for Labor.
* Key issues: health, ABC funding, education.
