I can't believe there isn't a thread already on here for Z17..... 
But anyway here's a photo from 1937...... 

Z17  Addington Road, east side, Selsdon 1 [1937]

Same Box...Same Date...Just taken 30 yards along on the left!   

An additional shot from Pete's Christmas thread, circa 1965:



And the location in 2018:

Thanks for posting Peter.

As there wasn't a page for Z17 here is the Data from old Metbox List:

Z17

A.R.W. Siren

02-Jan-33 Nov 67

Southeast corner of junction of Addington Road and Old Farleigh Road


District: Selsdon

Subdivision: Wallington

(Note: Per OS maps, this Box was actually located on Addington Road, east side, approximately 10 yards south of Old Farleigh Road on triangular island in centre of roadway.)


Old Map:



Google Street View:

https://www.google.com/maps/@51.3430981,-0.063112,3a,75y,96.82h,78.86t/data=!3m6!1e1!3m4!1sh2Fk75vToh0w3Lt9Sb_1jg!2e0!7i16384!8i8192?hl=en