Originally Posted by
sdorling
You cannot MFU a RTW ticket at all.
One of the fundamental rules is that in order to the MFUable it has to be on a return itinerary. Also, it has to be on BA metal.
It would be great if BA did bring in the ability to MFU BA segments but I don't think we'll ever see that.
I also think the rules state that the entire itinerary has to be on BA metal for you to be able to MFU.