Is it too late to split loan for investment property?

Hi all

Have been reading the forum for a while but this is my first post.

We have purchased an investment property for $445k and just finished cooling off, we've paid 5% of the 20% deposit, which was around $20k.

Our current situation:
Principal residence mortgage $700k
Refinance of principal residence (pending) $50K - to finance part of the deposit/stamp duty
Investment loan (pending) $356k

Problem: We are paying the remainder of the 20% deposit/stamp duty from our existing principal residence mortgage. Total paid from our principal residence mortgage is around $58k.

Should we have set this up differently for tax purposes and split the $58k from our principal residence mortgage? We've already paid $20k so is it too late to split that? Should we split the remaining $38k prior to settlement of just leave it as is? I think it will mean we have a "mixed use" mortgage and some interest will still be tax deductible, but it's just not as clean?

Keen to hear your thoughts

Thanks in advance

 

Yes. Yes but can be refinanced. Yes.

 

How did you pay the $20k?
If you used borrowed money from the main residence loan this can be split after settlement.
Not really an issue if you split quickly.

 

I paid it from our mortgage account, not the offset (we have extra money in both accounts).

I can't split the loan now as we have an increase in progress, so we have to wait anyway.

If i can split it after settlement this would be perfect, and I could split the exact amount that we paid for deposit, stamp duty etc so that it's clear what the funds are for.