Tax questions from potential expat (Melbourne)

Hi there,

I'm a Spanish guy who has been living in the UK for more than 5 years, and I'm considering to move to Melbourne permanently in about 2 years from now. Recently I've been looking at all the things I would need to do, but I'm struggling to find the answers for the following questions:

1. I've got an HSBC bank account in the UK. Can I keep it if I'm not living in the UK for a long time (hence no salary settled, as I would do so with an Australian bank account)?

2. I've got a mortgage in the UK, and I'm currently living in that property. My intention is to let it instead of selling it if I decide to move to Melbourne, because I also consider this property is a good investment in the long-term. I'd keep my bank account in the UK if possible, to use it for both paying off my mortgage and receiving incomes from renting it out. Is that possible to do? If so, would you advise to do anything before I move with regards to this? I've been reading about taxes but I couldn't make complete sense of that; would I need to do anything about that also?

3. My mortgage product will expire in about 3 years. Is it possible to remortgage living in Australia? I've been reading all kind of comments about this, so I'm not quite clear.

Thanks.