Also am I right in thinking that the oldest longbarrows around here in the southwest don't even have burials in.. then they might have.. then they have chambers. Dunno what my point is, maybe that they did get fancier in time.

Also the choice of chambers would depend partly on what stones were accessible? The ones in WKLB came from a long way away. Maybe they didn't want to drag hundreds over the countryside when enough would do. Or maybe they liked their bones cosy in just a few chambers.

Oh I don't know.