Forgive my ignorance here. But I was on an EDI-LHR-JFK-LAX flight that landed in Heathrow late and we missed the JFK flight. We were re-routed on LHR-SAN-LAX. This flight landed 20mins after the original flight was due to land and the SAN-LAX was economy only (the original flights were booked business)

Am I right in saying that I can claim for a downgrading and the 20mins late arrival? If so this is the world gone crazy.