Hi Wlecome to TY
. I also live in the UK.
Please tell me if i read this wrong. Your breeder didnt vet check your puppy before she came home? Your puppy was sent home eating cat food? YOur breeder didnt inform you if your puppy has been wormed, so she might never have been wormed at 9 weeks?
Have you swaped over to wet puppy food? Did you take her for her first injection at the vet? Here in the UK they get their first injection at 8weeks old and 2nd injection at 12 weeks old and then 2weeks later they can go outside on walks etc.
What did the vet say about het weight when you went to get her first injection (thats if you took her) xxxx