The Williams "Utility" model chainwheel (and Chainset) pre-dates WW2. It's listed in the 1932 Brown Brothers catalogue, which is the earliest one I have, other than 1920, in which it doesn't appear.
>From: Robert Murray <email@example.com>
>Subject: [CR]Williams 5 pin chainwheel
>Date: Sat, 31 Dec 2005 18:40:01 -0500
>I have a mid fifties Claud Butler Jubilee model club bike. All the
>equipment except cables, tires and frame paint, is absolutely original as
>my late friend purchased it in 1956. My question is the steel cottered
>Williams 5 pin chainwheel is not stamped as a Williams even though it looks
>identical. It is stamped as UTILITY Made in England. Could this be left
>over equipment from WW2?
>Maybe the British list members may have the answer.
>Snow shoeing in Toronto