Doesn't TransAero use a rather large bus on that route at times?
To be fair I think that the BMI J offering to Moscow was streets ahead of BA pre the switch to longhaul (so i heard) so it's about time they did something about it...
Looking at the end of this month, the largest I see UN using is a 763 and not every day. They typically use 737s. And yes, from what I heard the BD product was significantly better (albeit on narrowbody planes) and was similar to domestic J on AA/DL/UA transcon flights as far as the hard product goes.