Sorry, but the french fries at MacDonald's in Australia are vegan. They are fried in 100% vegetable oil and all the additives are non-animal derived. I've checked. Their website has complete nutritional information and ingredient lists available.
I agree that supporting them as a company is not ideal, but It's not possible to be perfect all the time, nor is it everyone's prerogative.
And you shouldn't beat yourself up about it, it was an accident, and your guilt isn't achieving anything, so don't worry.

They are! OMG! thats awesome! i always feel guilty eating their chips... because i heard that they added beef flavouring to the chips and i didn't know wether it was real or not.... because i do hate macas but sometimes on school trips its either eat macas or starve for hours and hours (and then be called anerexic from peers).
The 'natural flavoring comes from beef' quote is from 1997, and McDonald's have changed many of their ingredients and processes since then, mainly to try and change their status as unhealthy by lowering cholesterol and sugar from a lot of their products.
The fries at Hungry Jacks are also vegan, the onion rings contain Sodium Stearoyl Lactylate, which is commonly derived from soy, but can be derived from animals - you'd have to contact them.
They both contain palm oil, you'd have to contact them to find out whether it's from a sustainable source.
The new vegie burger is neither vegan nor vegetarian, it contains milk, eggs, rennet cheese and many animal derived additives.