Britannia never ruled here, in fact the US has had a lot more to do with Thailand than the UK in the last century. To the point where US businessman that come here can get visa's on substantially better terms than Aussies or Brits. Can't complain though- I got an easy residence in Hong Kong because it was a brit colony, but an American couldn't. In fact, the main reason I got my British passport back then (I already had an Aussie) was as a shoe-in to HK.

Both the US and Oz have free trade agreements with Thailand, so US produce won't be at a disadvantage compared to Oz on import tariffs or quotas. So if you reckon theres a market for your local cheese in these parts, persuade someone to import it. But you're never gonna get all those familiar things you had back home in Thailand, some stuff I miss too but I'm not much bothered- at least I can get vegemite.