The war would still happen, but the problem is whether it stays the same.
For every year that the war is delayed, Russia will be more powerful, the bases of a superpower that competes against the USA have already been built with French loans. (Austria-Hungary should also be mentioned, it was growing very quickly as well and in a few years it would be hot on the heels of France)
Geopolitics would say that the United Kingdom would remain neutral if it considers that France - Russia (and probably Italy) and Germany - Austria-Hungary (and probably Ottomans) are equal in strength.
A mutual destruction that leaves continental Europe weakened and licking its wounds without having to do anything is best for the British.
I wouldn't be surprised if they fund both sides just to prolong the war, or fund the side that looks like they're going to lose to avoid a quick defeat. And when everyone is weakened, the UK will impose a generous peace, where the winner obtains reparations or some territorial claims, but it will not be enough to be a European hegemon.
On the other hand, if Russia is very powerful, perhaps the UK will be forced to participate on the German side due to geopolitics. It's not that strange, the UK and France (enemies during the Napoleonic era) allied themselves against Russia in the Crimean War. Politics makes strange bedfellows.