Have they issued you with a BA ticket (125)? The reason I ask is that some online TAs (Opodo, for example) bill the ticket directly with the issuing airline. Eg, booking a ticket on BA thro Opodo results in two charges for me - the fare is charged to BA as a normal transaction, and then there's an Opodo charge for their handling/booking fee. Booking with more obscure airlines sees the whole thing going to Opodo. Not sure if Expedia do the same thing, but if so, you'd still get your extra avios...