Both BA and some of BA's customers are finding that some recent Amex transactions are being duplicated. The cause isn't known - and I don't know if it's connected to the problems last week or even the Gibraltar fix (by way of a pointless theory). But BA contact centre staff are aware of it, so (a) check your recent Amex transactions, and (b) if anything appears to be a direct duplicate then call BA, who are in a position to reverse the duplicate. There is a longstanding policy in this area anyway for accidentally duplicated transactions, so no-one should fret about this.