dnw, thanks for quick reply - fare difference - ex Lis - approx £ 1400, ex LHR - £ 2700!
We are fairly flexible with our dates, but it seems as though there is already limited availablity.
I thought about booking WT + and upgrading using miles, but everytime I try this, I only get a routing via HRE and I have tried everyday eitherside our preferred date for a week either way and it does not change.
I did think about booking regular WT+, which is available direct to JNB and then calling to ugrade as there is a not on the EC page saying to call if you want to upgrade an existing booking?

Thanks again