Originally Posted by
aksai oiler
However, your new website will not allow me to use my One World Status (only IB+) and will only allow me to input a 075 ticket number, and not any other airline which utilises IB for a code share (including your sister airline).

You don't have to input an Iberia Plus number.
And you can delete the "075" that has been pre-filled in the ticket number field and replace it with the correct prefix (125 for BA) if it's not an Iberia ticket.