I think if the house is 4 bed and >1500sq ft then they easily top ?1m from scanning rightmove. The 3 beds do cluster around the ?850k. The key is sqft really because i've looked at 3&4 beds (before the agent has a floorplan) that are actually circa 1000sqft and they feel hugely top heavy. Developers certainly seem to cram bedrooms in at the expense of space and practicality. Then you get the 4 beds that are 1500 - 2000+ sq ft and the feel/difference is huge.