Thanks for all the quick and thoughtful responses. Unfortunately, per the day flight, the only flights available using Avios are the flights I listed in my original post. I will probably opt for the earliest sleeper service flight then, and then take LCY-JFK. I will miss the galleries lounge at Heathrow, however. It's generally a pleasure to be there. Anyone with an ExperFlyer account nice enough to look up upper deck seats on the 747 flights on 12 August?