My DONE5 ex-MPM, quote from BA in South Africa:

FARE 42,140 ZAR (basic fare)
FEES 11,188.23 ZAR (taxes & carrier imposed surcharges)
FEE 250 ZAR (this fee is from BA in SA for their services)
TOTAL 56,578.23 ZAR

Route: MPM-xDOH-JFK-GIG-SCL-IPC-SCL-GIG-xJFK-HKG-NRT-SIN-CMB-HKG-xJNB-MRU-JNB
56,287 miles

My route does not pass through London, so the fees could be much higher. The route was determined by personal travel preferences, not mileage maximization. If the HLE airport ever opens up, it will replace MRU.

PS I know the figrues from BA in SA don't quite add up, but that's the way the quote was given.

The amount actually charged to my credit card on July 15th was ZAR 56,469, presumably because of exchange rate fluctuations. On that date, according to xe.com, ZAR 42,140 was USD 2933.78. The fare given today by expertflyer.com for DONE5 ex-MPM is USD 2792.02.