As mentioned earlier, and according to NAA, the Chusan did depart 10 Jan 1970 and arrive in Sydney 10 March 1970.
Whether they were BOTH actually on that ship is another story. I haven't yet confirmed the port of departure, but so far, her story on this topic checks out. Also keep in mind that they might've named their daughter after this voyage that I suspect at least she was on.
For those asking why the timeline of when they met is so important... it's because many doubt she met him in 1970.
Firstly, it's unusual for 19 year old with choices and her whole life ahead of her, to wait six years for a 31 year old man to get out of jail.
Secondly, WW departed Aus on 15 Feb 1970. How could he be getting on the Chusan on the 10 Jan in UK? Technically, he was still with wife IK in Australia.
The theory is, they met when he was secretly in Australia in 1974. They can't say they met in 1974 as he hadn't officially entered the country. They can't say they met in 1976 as they just met! And he's trying to hide his history of meeting women, marrying and changing his name (too similar to Marion's case). So, the only answer is to say they met before jail.
15 Feb 1970 – WW and IK depart Aus together, divorced (weren't even married a year!)
Early Jan 1970 – WW and DW meet aboard the Chusan departing Southampton, UK
10 March 1970 – Chusan arrives in Sydney
23 Jun 1971 – WW in prison, France for a long list of charges
21 May 1974 – WW discharged from prison
1974 – WW suspected to return to Aus but no record found
12 Feb 1976 – WW changes name to FDdH
20 Feb 1976 – FDdH marries DW
23 Feb 1976 – FDdH applies for Aus citizenship
25 Mar 1976 – FDdH Aus citizenship granted and Aus passport issued
28 July 1976 – FDdH and DW depart Aus
Please let me know if I got something wrong.