Thanks for your response. You are remarkably accurate with your base fare calculation -- it was 1,100 Euro, roughly $1,200 US. On my e-ticket receipt, BA lists an additional 500 Euro for Carrier imposed Fees, and 144.08 Euro in "Total Government Authority, Airport Charges" for an additional 644.08 Euro in total taxes and fees. I don't think they're including the Carrier Imposed Fees.

Side note -- even with the BA calculation of "base fare", I still can't believe the base for the AGP-LHR segment is 54, which suggests a Club Euro fare of 10 USD (not even Euro)