If a cat has lived rough, as you say yours had before moving in, they can be more prone to biting--especialy if they were under constant stress and learned that behavior as the only way to react.
My cat was my grandfather's cat first. And my grandfather was NOT nice to him. Fredward learned to bite as a way of getting his way. And also just because. He still doesn't like to be petted roughly, but when we first adopted him from my grandfather, he'd bite even if you petted him gently. I don't think he knew anything else. Cats DO bite; under stress and if that's what they've learned. Male cats will bite also because of territorial issues.
Now back to your little girl. If she's only biting when you're putting her back out into the workshop, it could just be because she doesn't want to be there! She may think she's being punished and therefore banished every night. Is it warm enough in there? When was the last time her bed was cleaned? And checking her to see if she is pregnant is a good idea, as chef-de-jour suggested.
Next time you have her inside, cuddle her just to make sure she's still receptive to you, then gently check her legs and paws. Gently run your hand down her stomach, etc. If she's in pain, she'll let you know! If it's not pain, and if you've cleaned her bedding and she still doesn't like the workshop, check with your vet to make sure she's healthy. Then if all that is resolved, consider moving her bed to a different place. She may just want to stay inside with the family.