Originally Posted by
dmahon
If your date is fixed, the best way would be to upgrade one way and throw away the return segment (book WT+ out and WT in, then upgrade the WT+ to Club) so less cash and only 12,500 miles. You'd have to do this on the phone.
In the end it depends on the cost of a pure miles booking (calculated out of the cash fare plus a value on the miles, e.g. I would value 50K miles at around £500) vs the alternative WT+/WT booking with an MFU. For the MFU-ed booking you will receive miles as well, which has to be taken into account. Note that the WT return leg (which will not be used) has to be booked into H class at least in order to make the WT+ leg eligible for MFU.
Pure miles booking: tax £182 + 50K miles == £682
WT+(T)+MFU/WT(H): cost around £1016 + 12.5K miles == £1141 - miles received, depends on your BAEC tier (4441 + tier bonus) - Blue around £1100
CW(I)/WT(N): cost around £1265 - miles received (5330 + tier bonus) - Blue around £1212
If you value 50K miles at £750, the pure miles booking is still the best option. I'm ignoring the TPs that could be earned.