I've just used one Barclays Avios upgrade voucher to book two Club award seats for LHR to BGI in January 2026 on the assumption that I can call BA to apply our other Barclays voucher to book upgraded Club seats for the return leg in a few weeks time at 355 days out, on the same reservation. Can anyone confirm that I have done this correctly? The other approach would have been to use both vouchers now and then ask BA to apply them to the return legs later but I'm not sure that would work.