Thank you, Ros, that's really helpful, and confirms my tentative findings. Ann's parents may have been at Kapunda or Burra Burra mines themselves, as they sailed for Australia just after Ann's marriage in May 1847, but subsequently returned to Cornwall around 1851. Some of the info I have is a little conflicting: John and Ann were married in Wendron Parish in March 1847, and he was supposed to have been convicted in October 1847 or thereabouts, though I need to check this info for myself. As I have already mentioned, he was then transported on the Bangalore in 1850, so I would assume that their first daughter (also Ann) was born in Cornwall, yet there's a birth registration for her at Adelaide in 1847. I haven't yet discovered exactly when Ann senior went to Australia. My initial assumption, before I discovered her marriage, was that she'd gone out along with her parents and a number of her siblings, but now I'm not sure. I've read up on Tickets of Leave, etc, and it looks as if John was pretty much earning a living and living independently quite early on in his time as a convict, so presumably Ann was with him in Australia even while he was still working off his seven year sentence.
