Originally Posted by aaupgrade

In my limited experience, I find that who issues the ticket does matter, as I have had no problem upgrading flights on a BA issued DONEn to first using Avios. Whenever I plan to upgrade DONEn BA segments to first I book the DONEn through BA. For example, most recently on a BA issued DONE3 I upgraded LHR-IAD to first and my upcoming PVG-LHR has also been upgraded to first, in both cases using Avios.

If there is a non-published ban, then your statement should probably be modified to read "the problem is BA's non-published ban on upgrading DONEx tickets issued by other airlines".