The Electoral rolls can be misleading as well - often people didn't change their addresses etc- so they could show being married to/living with someone when the situation had changed - 1958 is the only one WSB & Dorothy were not listed ( I also checked Doris Elsa ).

Question: does anyone in the family know how long WSB and DELB had separated for? The baby was born 1955, and yet 3 years later still no sign of Dorothy in the 1958 ER. Does Irene remember events from that time? Who looked after the other children? Did they stay with the father or get put into foster care? Did Dorothy actually return home? Often the Welfare Department becomes involved when children are in this situation and there may be records...amazing little snippets often get jotted down ...just a thought....memories may be jogged with a few gentle questions:-))..it might still be worth checking the relevant departments for the family BLUNT ( rather than just the adopting/ foster area )
Finding errant fathers os often a trial:-))

there were folk with the name HUNTER in the Mt Gravatt area in the 1950's but no George or Gordon...also how sure is everyone that his name was HUNTER??

has anyone purchased Dorothy's death cert? It might bear very hard news, but at least you will have whatever info there is there.

Times were very tough in the 1950's, Post war and women forced back into the kitchens to make way for returning soldiers employment

Anyway, if you come up with any more clues, post back and the sleuths will have another try:-))

Cheers
Jocelyn