My contention is that change of carrier on a RTW makes no difference and in fact I had another conversation with BA and a supervisior in BA today who agreed with me that there is nothng in the fare rules that allows for a change fee when keeping the same route but changing the date and/or carrier.

Perhaps on a non-rtw I could maybe see the logic but there is a fare for a rtw for all carriers.

So lets see - its currently back with BA ticketing for them to justify why there is a change fee (or any other fee for that matter) when there is nothing in the fare rules.