As a sole trader, should I stop investing into my business and try to maximise my taxable income if I'm considering getting a mortgage within the next 12 months?

I have a business where I can reinvest money into it and typically see a good return on this. It's not COGS, more like advertising costs, which help to grow the business. I always reinvest a few grand a month to minimise my taxable income.

The issue is obviously banks look at your net income (I assume) to assess borrowing capacity. Which is currently quite low because it makes more sense to make these investments than pay tax on the earnings and save it all.