I am very grateful to Penelope Monkhouse from Germany for her continuing support of my project. Penelope has suggested another anthology which I am trying to locate. It is in English, French and German, entitled "Ohne Hass und Fahne No hatred and no flags Sans haine et sans drape". The Editors were Wolfgang Middleton, Christopher Schonherr and Herbert Depp. It was published in 1959 by Rowohlt Verlag.
As soon as I have more information, I will report back.
I should also like to thank Clive Bettington of the Isaac Rosenberg Statue Appeal for his continuing support and guidance.