G,day Lee
I have seen Centaurus A with a 200mm Dob from a suburban site (closer to Perth CBD than where I live now). While quite faint I could observe the two halves of this object. At my current location on Perths urban frindge I have seen Centaurus A with a 80mm refractor and even noticed structure and a couple of foreground stars with averted vision. With a 300mm Dob the galaxy looks like a hamburger