Note that when an English person says the north, they expect everyone to know they are talking specifically about the north of England, not the north of the UK even if everyone else is talking about the UK.
Basically the names of geographical regions don't always make sense.
No normal person refers to Scotland as "north UK" when they could say Scotland, though.
It was once common, and in modern times it's occasionally used as a deliberate affectation.
On the other hand, Balham was the "gateway to the south" (which reached as far as the Mediterranean).