Let's start off with the obvious. Both France and Britain naturally had their 'men in Petrograd' (Bruce Lockhart being the most notorious) but I suspect you're interested in German support for the Bolsheviks. This has been a common trope since 1917, most obviously with [edit: Lenin's] notorious return to Russia via a German 'sealed train'. This has been often misunderstood as German backing for the Bolsheviks but was in a more general act of opportunism by Berlin - Menshevik leaders in Switzerland (including Martov) took the same train a month later. (Conversely, Britain detained Trotsky on his return to Russia, before the Provisional Government demanded his release.)

The other major rumour surrounding the Bolsheviks is their receipt of 'German gold' during 1917 to finance their activities. Originally published as a Provisional Government smear following the July Days, I've yet to see any evidence that there's truth in the accusation. Rex Wade (The Russian Revolution) describes it as an 'enduring conspiracy theory'. And, in truth, it's hard to see how German money would have affected either Bolshevik policy or the attraction of this to the Russian populations. While clearly anti-war, the Bolshevik line in both 1917 and 1918 can hardly be described as 'pro-German'.

While Lenin's return to Petrograd was important, none of the above would have seriously impacted the root causes of the Revolution, which lay squarely within Russia.

On a more abstract level, the war itself was a massive intrusion into the economic and intellectual life in Russia. And the policy debates/struggles amongst the Bolsheviks and Mensheviks have to be placed in the context of Second International politics and frameworks. But I don't think this is what you're asking about.

You are maybe getting confused about the count-revolution, involving 17 countries including the US & UK.