The trade off that you need to make is between where you work, where you play, and where you live. There is no right answer. My wife and I choose to pay a king's ransom to live centrally (Elephant) because we both hate the very thought of commuting. But I look around me and see small flats being sold for a quarter of a million pounds. It's insane. Our rent is at £1300 a month and we consider ourself lucky to get a two bed with a separate kitchen for that.

Anything too good to be true almost certainly is. There are a lot of scammers out there.

If you can find a private landlord, it will be cheaper, probably better, and probably more stable.

The only other piece of advice I will give is this: don't buy. Either London will enter a period of long term decline as the world economy reshapes itself, or a future government with a pair will lay waste to the suburbs and build five or ten times the number of houses overnight. Either way you will lose.