This is from Needlework Illustrated issue 185, which I found in Oxfam charity shop in Totnes. It’s a post-war magazine, but has no obvious date. Rather annoyingly the pattern is spread throughout the magazine, but I’ve edited to just the relevant bits and duplicated the chart in a bigger picture size. I love that on page 2 the jumper is modelled by “Mrs. Anne Rawnsley, well-known for her impeccable taste in clothes.” I’d like to be known for impeccable taste one day.
Here is the Google Docs version.