This brings me to the next section: Once you're in London, one of the first things you'll need to decide is where to live.
When I've pointed out to them that I'm also a foreigner, they generally say something along the lines of Still, in my experience, this is an extremely rare conversation to have and it's one that you could have anywhere.
Postcodes are a common way to identify roughly where you live and they correspond very loosely with compass points from the City of London.
It's worth noting that there is no NE postcode or S-only postcode.
If you can stand some uncertainty, it's probably better to pick a place once you're actually in London so that you can get a feel for different areas.
I would strongly advise against buying a place until you have a good feel for an area, as buying and selling property is both expensive and time consuming and it's worth getting right the first time.