I believe that one of the UK SWP members wrote an excellent history comparing shop stewards movement in Western Europe in the period 1914-1919.
A communist party is not relevant to a revolution occurring.
In 1917, the Bolshevik faction was miniscule, and Moscow was carried by the geographic Soviet and factory Soviets. Similarly in the German revolution the shop stewards were fundamental, and until the early 1920s, the steward organised KAPD was larger than the III International Bolshevik KPD. Stewards too in Italy, and in France, and in England.
The best way to cause a revolution in England in 1915-1921 is sovereign default, hyper-inflation or hyper-deflation, a collapse in working class living standards, and an inability of factory managements to control nascent industrial unionism in the form of shop stewards and factory committees.
* * *
However, any revolution is going to face a crisis as the Socialist movement in that country splits between a kind of Fabian Social Democracy (the pro-war II International parties), and the revolutionary position.
In Italy and Germany the revolutions were hamstrung by the strength of the Social Democrats, and by the amelioration of the worst of the crisis by the new position held by the state. In Russia, continuing crisis meant that the Social Democratic parties, the SRs and the Mensheviks, became discredited. In fact, as the workers councils grew in strength in Russia, many members of the Social Democratic parties moved leftwards (the Left SRs) or joined more radical parties. Even the Bolshevik Party was radicalised by the continuing crisis and the presence of real workers councils.
The ideal condition for a "Weimar" Britain, is for Britain to default on a massive debt crisis, which causes workers councils to further radicalise, and the Labour Party to split in two; but, that Britain still has enough economic clout over the Dominions and Empire to barely survive but in constant crisis. It would also help to cause a "Weimar" situation if the Tory and Liberal parties were torn in two over an issue.