If you don't live in Sydney, as I do, Potts Point might sound upmarket to you and the word, "Chapel" appealing. But they married at the Wayside Chapel on 20 Feb 1976 which was, in the 70s, a hangout for drug addicts and homeless as the chapel helped them. I used to visit lonely old age people as a Volunteer in their homes in the Kings Cross area on Saturday afternoons. When my parents found out, they banned me from going there. An upmarket wedding in Sydney would be held at St Marks, Darling Point. So I have an idea that her parents would not have attended if they were like mine. It is also very small.
However wouldn't they think it strange that Diane was marrying a man who had changed his name since they met him??? If the Chusan story is true??? And the Hilton Hotel, South Hampton where he said he introduced himself as WW???? Or was the deH name already in use???
The Chusan story is definitely not true as he was with Ilona at the time and "could not be in two places at once". You will never find their names on any passenger lists IMO. Maybe the parents travelled on it some time and Diane was told she was conceived on that ship perhaps so her daughter's second name is Chusan.
IMO Diane met him in 1975 (or 1974 perhaps?) when he worked for her parents in their cafe in Sydney using the assumed name of Frederick De Hedervary - hence she called him "Rick". So then he had to change his name to that name before they got married. It doesn't make sense to me that his name was Willy but she called him Rick.
He could no longer use Willy Wouters as his name as it would lead authorities to find out he had a criminal record so he would not get resident status here.