Ella, I cant find any of them after 1861. I wonder if they didn't all follow Ann?
There are a few deaths for Thomas Miles; apr 1855, oct 1857, jan 1864, oct 1865.
Ann senior states she's married on 1861, so think the earlier ones can be discounted, but I'd put my money on them all being in Australia by then.
There are a few different sites you can use to find births, deaths, marriages. I'll pm you details.