Tried to do a dummy booking for this (hoping to include a stopover in London) but get an error message that BA does not fly all or part of the route. But they do fly from BDA to Gatwick and LHR to EZE, so would a book and upgrade to CW have to booked over the phone?
Secondly, any idea how many points it would take to get to EZE from BDA via LHR, and what the Premium economy ticket might be, roughly, in US , for a trip in April?