NW11 Golders Green: why this London postcode has the number 11

NW11, Golders Green, is not in the Post Office's list of March 1917, which prints Golders Green's streets under N.W. 4 (Hendon). A history by the Hampstead Garden Suburb residents has the Suburb's post addressed NW4 until December 1920. NW11 took the next free number; by name it would have followed Cricklewood (NW2). A 2017 study calls NW11 and SW20 “added later out of sequence”.