They were more insistent than any other bus loaders I recall ever seeing, someone had to finally point out that all the empty room they saw in the aisle towards the back (which wasn't much room anyway) was actually a few small children standing in the aisle, not empty room more passengers could be herded into.

Admittedly I don't have much experience with such buses since 98% of my travel is within the US and they are rarely used for such purposes within the US, I'm sure it's worse in some places, but I kind of expected better from BA (this being my first long-haul experience with them, having only flown them for a few intra-Europe flights previously).