Planing to use my 2-4-1 to fly BA metal from IAD to EDI (via LHR). Then, from EDI drive to ABZ. Then fly ABZ with a stop at LHR. Then, LHR to IAD. I can't find a way to book this using Avios 2-4-1 on-line. Is it possible, or should I call and hope I am not charged an extra fee?