interest rates, page-36

The idea of financing it over 30 years is not to use the full term but to maintain limits on your repayments.
You can then make extra repayments that you can afford.

So in effect the term is irrelevant unless you set too short a term.

(given that interest rates are going to explode soon - remember)

Combining inflation and wage growth it should allow you to pay extra off the loan and repay it early!

20% is standard deposit, LMI is not something that I would entertain the thought of nor would I suggest it.

Good luck to you!