Jas, give the sugar soap mix a go... if it worked in DH's shirt with old napolitana stains it may work?

I also gave it another go soaking BIL's white singlet that he spilt a whole red slushie down the front of (BIL is 16yrs!!!)

He did it on the weekend & I only found the singlet Mon night
I soaked it Mon night & washed it today... back to white again

Cai - I add the oils to the white vinegar in the fabric softener dispenser too