One strategy my friend uses a lot when we play with all NAs is putting a factory in Australia with the colonial garrison NA. On the first turn he brings his India fleet to the bottom of the map but out of reach of the Jap so it can merge on UK2 with the aussy fleet. The factory being free, he can still build an AC if he wants in London, but he has now a lot of option in the south pacific. Combine this with the US island hoping, the allies can have a mighty fleet in the pacific to put some pressure on the japs without too much expanditure from the UK (maybe one fighter to full AC and some inf for the transports). Combining UK fleet and US fleet (both of which are mostly defensive given the AC, unless US spend a lot on ub or DD) make it almost impossible for the Jap to take it out without loosing all of his in return. For the final punch after increasing the size of the fleet, you can use a joint strike to attack the jappan fleet.
I guess this wouldn’t work too well without NA though.