We took a£50. Deposit on a puppy .then had bad feelings about buyer after checks found out she had 10 dogs removed by rspca we offerd her deposit back as not happy letting puppy go for its own welbeing she wants full price who is in right

Both of you are partly "right".

You breached the contract by refusing to deliver the puppy as agreed.

But the measure of damages would probably be the £50 deposit. How does she think she is entitled to anything more?