Originally Posted by
BearX220
Quite right but OP wants to apply a 2for1 to the entire return itinerary, which calls for one res, one PNR, etc.
Except that BA has allowed people to do this for some time now. If the inbound is out of range when the outbound is booked with the voucher, when the inbound comes into range one can either call or if you have enough avios book the inbound as a separate oneway online and then call in the morning for a refund of half the avios. In essence, this becomes a return booking for purposes of the voucher.
From the companion voucher thread wiki:
Important update, posted by cbagent on 12 Feb 2018:
If adding the return sector to an existing one-way Amex 241 where the inbound dates were out of range at time of booking, it is now possible to book the flights online as a new one way Avios booking then call BA UK office when open.
Half of the Avios on this new booking will then be refunded to reflect Amex voucher use. The benefit of this is that there is no need to try calling open BA office in the early hours of the morning and the downside is the itinerary will be ticketed as two one way bookings. In addition the Avios balance must be high enough to take a debit of double the required Avios albeit for a relatively short time. May be of use for some people. Note: you are strongly advised not to use this new method of booking two separate one ways if going to the US/Canada. When booking as two separate bookings and having the 2-4-1 applied across both is that taxes/charges/fees are not recalculated when the voucher is applied across to the second booking. Sometimes this will work out well for you (bookings exHKG for example), but for exUS or exCA bookings it is not recommended at all since exUS/CA taxes/fees/charges are very high. As an example, using the two separate bookings method on a LHR-JFK booking in J or F for two people would cost you about £480 more that the old method of calling and adding the inbound to an existing booking. Please see post 965 here for more information.
https://www.flyertalk.com/forum/brit...2025-a-28.html
As noted above you wouldn't want to use this method ex-US due to higher taxes and surcharges.