The most expensive configuration I can find for that size (111 sq m) is 327,000 GBP on the cost estimator: https://www.wikihouse.cc/cost

Maybe you put in 1200 sq m instead of converting from sq ft?

did you maybe type 1200 square meters? i'm not getting that price at https://www.wikihouse.cc/cost

Where are you getting that number from?