Originally Posted by Often1

Presumably the cardholder, OP in this case, received £10,000 worth of goods and services in return for the amounts he paid to Amex. That too is a wash netting to 0.

I also do not believe that the BA-imposed requirement that both passengers travel in the same class of service nets OP anything. BA is free to seat any passenger anywhere it wishes and routinely violates fare rules and other conditions in IRROPS.