For the MG 4, that is one of the locally produced models and they have cut the price in Thailand several times. Might be something to do with the local factory overcapacity and the fact if they don't sell enough locally produced models they will have to repay the subsidies on the Chinese imports.
And yes the individual market conditions are probably the main factor and it shows that Australia has a very competitive car market...Thailand not so much which is why outdated Toyota are still number 1.
The UK is a basket case and not comparable with the ridiculous 20% VAT plus 10% customs duty on car imports. Also there are millions of "disabled" people who get new cars for free. In the UK, the Motability scheme accounts for roughly 20% of all new car sales.