Is that all?
Middlesex doesn't exist by the way - you're in Hounslow or Richmond upon Thames. I'm guessing you're just on the Hounslow side as in the amazing area you would be in in Richmond, St Margarets, you wouldn't get close to buying a house for £400k.
You live in one of the more expensive areas of the most expensive city in the country, and one of the most expensive in the world.