Thanks for the advise everyone.
Penny has been with us not for 5 days. She is just adorable. She walks well on the leading, quiet in the car and just wants to snuggle with me all the time. Alfie on the other hand is a wee bull and very vocally.
We took her to the vet on Monday and found out she has a severe heart murmur.
So just have to keep an eye on her.
Both of them still snarl and growl at each other. Although when we are not looking we have noticed her jumping around him like a little rabbit in a playful suggestion. And noticed him sniffing around her. So hoping that they will finally come around to each other.
The only other thing is that the pound said she eats wet food. I would sometimes mix a bit of wet food into Alfie's kibble in the morning and he loves it. So was trying the same thing on her and she was just picking the kibble out and eating the wet food. I was getting worried she wasn't eating enough so adding a bit more wet yesterday to her food with plans of gradually reducing it. But she never went near the food at all. But by night the wet food had cleared from both bowls so I am not sure who ate what as I have noticed her going to his bowl and him going to hers. Well this morning when I did the same thing even he didn't eat any food. That is not like him as before we got Penny he scoffed his morning food.