Can anyone tell me an international number of BA OnBusiness in the UK?

I'm in ZA having flown LHR-JNB and wanting to change my return. The published number for BAOB is an 0844 which isn't accessible from ZA. The locals can't change the booking, even the ZA BAOB office. All any give me is the 0191 490 7901 call centre which puts in a *long* queue before I can even ask to get to the BAOB office.

And even the BAOB office couldn't offer a direct line apart from 0844....

Eventually got it sorted after prob ukp50 on the mobile, but surely it's obvious you need a direct UK geographic line, as there used to be?