As much as I enjoy YOLT the movie, a couple of things always perplexed me from a practical point of view. First, how do you construct a rocket base on someone else's territory - even one hidden in a hollowed out volcano - without the authorities noticing there might be something a bit out of the ordinary going on? Rome wasn't built in a day, and I'll bet SPECTRE's rocket base wasn't either!
And secondly, the locals on that Japanese island might have noticed some highly unusual aerial activity around that volcano - molten lava is one thing, helicopters and a couple of missile launches is quite something else! - yet the only odd thing they report is the death of an ama diving girl.
Ah well, best not to think about these things, just sit back and enjoy the show!
As for Blofeld's business partner, I always assumed it was "Red China" - then going through political convulsions internally, shunned by the UN, and with both the US and the USSR hostile. China setting the West and the East against each other was a plot trope of the era in other media - for example there's an episode of The Saint called "The Gadget Makers" which has Russian agents being killed off and assassination attempts on MI6 agents, until Simon Templar discovers it's all a Chinese plot.
I doubt a similar storyline to YOLT in this day and age would feature China as the villain, not least because of the lucrative Chinese film audiences. North Korea, on the other hand.......