MAN they confused a lot of people with the quirky UK rules.
It is very confusing until you get used to it.
Only the cash on hand, incomes, capitols, and building of units are separated. All units move together in concert, as one big menacing Empire. The UK, USA, and USSR are all very mighty! Even ANZ and China are forces to be reckoned with. Look out, Axis!
Tech is not even separated. You can pay 1 IPC with London and 4 with Calcutta to buy a researcher. Very nice little benefit for the UK to use odd IPC’s up. A loophole, if you will.