I wonder if anyone can help me - I am trying to book myself, Mrs DrP and Miss DrP(Infant) on a MFU from WT+ to CW but cannot seem to find the option for adding Infants on the BA Book and Upgrade page as I can see from the Ultimate Guide that 10% mileage is required for Infant MFUs.

I hope I am not just being super-dumb and missing the button? or do I have to call EC?