Welsh Anarchist groups in 1915 (of course, can't be 100% certain these are anarchist, But 'Ferrer' looks a pretty good bet.)
"Just looking at a two page article in Tierra y Libertad from 1915 reporting on the Peace Congress in La Coruna that year. Interesting that among the groups/individuals/publications sending messages of support were these from the UK (Inglaterra is cited but I think it is Wales):
Reivindicacion (Vindication) Dowlais
Pro Prensa (Pro-Press) Dowlais
Ni dogmas ni sistemas (No dogmas, no systems) of Dowlais
"Ferrer" from Abercrave."