Moving to London: need tips

Hi, I've just got my visa granted so I will be moving to London within this 3 months from Australia. I was just wondering if anyone can give me tips on the following subjects:

- opening bank accounts: i heard this is quite a hard one to do, can anyone help me recommend which bank to go to and what documents I need.

- Finding room to rent: not too sure how I'm gonna tackle this since I haven't got a job yet so not too sure which area I should be looking at. But is there any area that I should avoid completely like high crime rate or dodgy suburb?

- Getting a mobile phone sim card: where to go to get one?

- Tax matters: I think everyone needs to get a National Security number to work in UK, am I right? Just curious how the taxes will apply to me and if there's any extra document i need to do to work in the UK.

- Driver license: not really a priority but just wondering if it's worth it to convert my Australian license to UK one so I can have extra identity card.

- anything else that is important to consider and need to know before I move.

Looking forward for input from everyone~~ thanks a lot!

Cheers

Githania