I have heard that people save by paying more tax then they need to. It is just taken out of their pay before it even hits their account and when they do their tax return they get it all back as a lump sum. It seems to be an easy way to save and there is no chance that you will spend it.

We have $30,000 it's still not enough, we're trying buy regional too. It's fucking ridiculous.

You need to work on increasing your income, learning to manage money & wiping any other debts (including credit cards) first. No bank will give you a loan because 45k won't even meet the new lending rules for minimum expenses before they'll look at a loan. If you do apply, the rejection goes on your credit record, so don't try until you can afford it.
Also, if you're only able to save through forced strategies like overpaying tax then you're not ready for a mortgage. I also doubt banks will see overpaid tax as a savings record.

How many kids have you got ?

Barefoot invested

Can you increase your income at all? Even cleaning a house or babysitting - an extra $50 a week would be $2600 a year. you will need to be really focused and save every cent you can for quite a while to achieve this.

we struggle on combined income of 150k

It is impossible

I'd talk to a broker, they can help identify how much you need etc. I'd look at your expenses and try and cut down the mobile and internet, then the electricity have tv free nights, do all your washing etc at night time. You can do this but from everyone Ive spoken to they all did massive sacrifices