Well apparently this is the history of Number 8 and we were all partly right in what we said.
From Wikipedia:
Following the construction of the house Gail and Martin became the owners and moved in with their children Nick, Sarah and David. Martin moved out in 2000 after divorcing from Gail. Gail's third husband, the serial killer Richard Hillman, attended to kill her and Sarah, David and Bethany in the garage, before then driving them into the canal. They were saved.
In 2011 David got married to Kylie Platt and she moved into the house. Gail remortgaged the house in early 2013 to start a new life with her mother's ex-boyfriend Lewis Archer, but Lewis took the money and ran. A betrayed Audrey chose not to bail her daughter out of her debts and instead loaned David and Kylie money to buy up the house, ending Gail's reign as owner after 22 years. But she took advantage of the situation by making it clear to them she was now just the landlady, and they were responsible for now paying for maintenance.
The garage was converted into an annex for Gail to live in. Callum Logan's body was hidden underneath the floor for several months after Kylie Platt killed him, although was uncovered when a van crashed into the building. The blame was put on Jason Grimshaw's late father Tony Stewart, as he was responsible for building the annex in the first place. Gail found it difficult to return to her annex due to sleeping on top of a body for many months, so Kylie and David moved into there.
Eight years after losing ownership, Gail became the owner once again after winning the house in a bid, money which she used left to her by her late father Ted Page.