mono-stereo Aye, the 10 abreast 777s are a pretty miserable experience - one of the reasons I avoid them when flying economy. I think BA still have 3-3-3 on a very few of their 777s, but they’re used on routes so interchangeably that I find it’s not worth the risk. Plus - really not a fan of BA’s economy product at the best of times…
I’ve flown 3-4-3 in Economy on a Qatar 777-300ER from Doha to Melbourne, and that was ok, but helped by the fact that we’d slept well on the A380 we flew from Heathrow into Doha…