We are taught in school that words ending in S in English may or may not have an apostrophe.
But in London you can almost forget about it, because there is a lot of confusion in this matter and there is not much to do with logic.
I'll try to clarify a bit below, but I guess it's still be confusing.
Everywhere with an apostrophe, but football team QPR disagrees.
St James's Park
St John's Wood
Generally always, but the texts on the tube station platform are different.
As a rule always, rare exceptions in the market.
Actually this area was never owned/ruled by barons.
Although the name is derived from the surname Bounde, there is never an apostrophe in the name.
Also by surname.
This was once the land of the canons. Monks have always been stingy, they save one character here as well. :-)
Named after the coal burners that once operated here. I really don't know whether to write Collier's or Colliers', either way.
All by surname and traditionally without the apostrophe.
There used to be an apostrophe, but it has been abandoned after the name of the tube station.
Use an apostrophe in tube station and district names, but not in street and exhibition centre names.
Is spelled differently in books, maps and street signs.
Queen's Road (Walthamstow)
Older street signs used an apostrophe, newer ones do not; however, it is always in the name of the station.
Queens Road (Peckham)
Street signs have different spellings.
St Margarets (Richmond)
The street and railway station do not have an apostrophe, but the church that gave the name does.
God's Own Junkyard
A quirky gallery in NE London. Google offers an apostrophe, but locally they think otherwise.