I have the same issue as you and haven't found a way to completely remove the Iberia number. The Iberia number is down as the FQTR and BA as FQTV. My understanding is the FQTV should be on pass but can't confirm (well I can let you know in May after I fly ).

There was some discussion on it on the thread below. There is a trick do it when booking but that is too late now.

https://www.flyertalk.com/forum/iber...-flight-2.html