I didn't see the trip report, but even if the OP left Victoria Station in an Aston Martin, this is cutting it too fine.

I'm appalled BA didn't charge him the £3500 cost of his o/w ticket LHR-JFK. I guess the problem is with their inflexible tickets that's there's no middle way: you either change it for free or you make the passenger pay a hefty sum for a new ticket. What they really need is a way to charge a stupid passenger a reasonable change fee - something they will cough up, but enough to discourage them from missng thier flight in the future, say around £1000 in this case.