Its a shame things turned out the way they did.. especially when you paid £500 for her, thats a lot for a yorkie here and you would expect a little more from the breeder.. unfortunatley thats not always the case though.
She sounds like a really healthy weight
Poppy was like that for the first few nights too.. she would go to sleep around 9/10pm, wake up crying about 1am, then again about 3am then again around 6am for her breakfast.
Now she is much better and she will sleep all the way through the night without a peep.. only time she cries is when I wake up and I go to change her water but thats just because she wants out of her pen
Does she sleep in your bedroom?