Multiple referral discounts?

I was hoping to use the two referral discount codes I’ve earned on my next order, but can’t seem to find an option to let me use both at once. This seems a bit silly since if I wanted to order 4 bags I’d need to make 2 orders. Is there any chance of getting them stacked, especially in light of the student discount being removed?

Huel don’t allow more than one referral discount code to be used per order.