Last year my flight from LHR was delayed due to a typhoon in HKG - 5 days until I could get a new flight. The expenses allowed were, in my humble opinion, generous, and I received very fast support via X/Twitter. I made my claim when back in HKG and was paid into my bank account within a few days.
The only confusion in the whole process was when the flight was cancelled and I had to rebook. Via X/Twitter was very good, trying by phone was very slow & difficult.