"Op shop" is an abbreviation for "Opportunity Shop", yes it's a charity or thrift shop. It's a unique Australian term I think, but I love it - so positive, it hints at treasure found rather than cheap clothes discarded and bought by poor people.
We moved around lots when I was a child - once a year on average, and the Victorian house was my favourite. Sadly, it's recently been demolished - it's in a prime spot and I expect they'll build apartments there. Such a pity. I visited in when I was in Sydney a few years ago and it was old and neglected, unloved. The land would be worth millions though, so this is the way it goes in our culture unless money is not the most important thing.