I have just the CPT-JNB-HRE legs left of an e-ticketed AONEWC4 (with actual dates at the insistence of BA when issuing). The only reason I would want to go back to HRE is to start another *ONE* trip - but the latest fare increases have put paid to that idea. I am trying to re-issue with CPT-JNB-MRU once BA starts the MRU flights, but BA in HRE says I can't. If they don't relent I plan on not using the last coupon. From what I read here this going to be some sort of problem?

I can't see why BA should mind since they have to provide one less flight. Besides when I missed my flight to HRE BA just pocketed the money and I had to buy another ticket.