Iberia has nothing to do with an LHR-GLA flight (well, it could be a codeshare). If you did a AUP at the airport for LHR-GLA, I'd expect the flight to be rebooked under the BA prime flight number and then the Avios/TP would come from BA and not from IB (and BA does offer the higher amount in the case of AUP, unlike IB/AA/MH/others).