@mendip - how does your daughter deal with the cold/ snow? I think you've brought her to England during Christmas break? How did she fare during winter?
As for Perth, as I understand there's winter too but doesn't reach 0 degrees and no snow. Also, I think TH to Perth is nearer than TH to UK? (cost for airfare, etc). An advantage of Perth is that "Uncles" BLD and Terry can watch over her sometimes. I think the younger son of BLD is similar in age to your daughter.
@BLD - have your sons lost their Filipino accent? You said before that your sons were developing a Filipino accent due to the teachers in the Int'l School in Laos. Are they now saying "G'day mate. Let's have shrimp on the barbie!"