Debbie just flew LAX-LHR in 36H. Lots of legroom but she did mention the seat was slightly narrower because the IFE screen in in the armrest. She got lucky and 36J was empty, so it worked out well for her.

Debbie says row 35 A/B or J/K are good. "Those are the ones to go for."

You aren't going to like row 34.

I'd avoid row 59.

Are you able to buy a skycouch? It would get you an empty B or J seat. Anywhere between 38 and 44 isn't bad. But be warned the skycouch on either side of you might be a kid's zoo.