It's all about location, location, location.
It's all very well giving links to stately piles up country - but no one would pay good money, no matter how nice the house, for somewhere, rural, no amenities, poor schools choices and a trek into London.
Surbition is slap bang in stockbroker belt.
Hence a 1 bed flat in a reasonable area of London is 300K, and you could buy a whole terrace in a pit village for that.