Rag, Jim claimed they went in 1922.
They went in 1918 and came back in 1922.

Jim,
how else would you describe being blackklisted from work?

They were not, except for sensitive work requiring security clearance.

the people who went were not subversive revolutionaries - they were democrats fighting fascism

Guardian,
"The Communist party of Great Britain took responsibility for organising the recruitment of volunteers in Britain, and leading communists held positions as officers and "political commissars" with the British battalion in Spain. While historians have tended to see the members of the British battalion as genuine volunteers rather than as communist "dupes", the rhetoric that the communists used in the civil war (defending "democracy" against fascism) sits uncomfortably with the excesses of Stalin's Russia at the height of the terror. The degree of political control exercised by the communist leadership of the battalion, and especially the treatment of those volunteers who fell out with the political commissars for political reasons, has attracted particular debate."