I think the new turn (with J going before UK in both scenarios) order really works against a British Factory purchase.
An Aussie IC seems doable, but I don’t know, its still feels pretty shabby as an island at only 2 ipc. I mean if you have to buy a transport, that’s only one other ground unit in the first turn. Unlike India or S. Africa where you can eventually get those tanks to Russia, Australia requires you to transport everything. It seems safer in 42 than 41 probably (41 feels risky to me, unless your transporting units from India to Australia in the first round), but in 1942 you have the issue of no starting fleet in sea zone 42, which make the whole investment seem a lot less worthwhile.
If the UK was meant to have a second Factory they should have built the Colonial Garrison into the game. With all the other rules floating around, it would have been relatively simple by comparison. Its really the hefty price tag at 15 ipcs that kills it for me. If it was one extra factory for free, or all factories were only 12 ipcs, things would probably work out better.