Delta were magnificent. All really helpful and a joy to travel with. Food was very nice and they kept me topped up wthe water, cold drinks etc. Heathrow was very busy that time of day and despite arriving early I needed all the extra time to queue to check in luggage and then the waiting to get through security was very long and only just got to the gate as it was closing. You need to aim to be in Heathrow 3 hours before take off, not two.