Hi there Melissa
Puppies can be frustrating and stubborn, just like the rest of us
In the ideal it would be easier if you could take a few days off work. Try and position these around the weekend so you get as much time with her as possible. She is a little older so retraining her will take a lot of effort, that's why you need to be at home with her for a while.
As for the puppy mats i would definately want you to take them out as well and just have the crate. But i can understand the reasons why you don't want to do this.
So here is the ideal way to help solve this problem. Whenever you are not at home she should be in the crate. When you are home you need to take her out as frequently as possible first thing morning and night, before and after play and before and after feeding. You seem to already know when she needs to go the toilet so take her out when you think she needs to.
When she is outside take her to her toileting spot as you have been doing and give her her command. If she doesn't toilet after a minute play a little game with her in another area of the yard. Take her back to her spot and give her the command again. If she doesn't go repeat.
You will have to repeat a few times until she is so desperate she has to go. At first this will take a long time for her to go but after a few times she will start to get better so don't give up
Remember to always use a deodouriser inside when she messes because dogs are very much creatures of habit and smell plays a huge part in that.
If you do catch her as you have been growl and her and take her outside just like you said. Taking the soiled material outside is also very important so you are doing everything right.
Make sure her toilet spot outside is always the same place and for a while you may need to put the pads out there. As she slowly becomes use to it you can slowly remove the pads until she doesn't need them anymore.
The last way that takes a huge amount of time and a lot of mess. Is to slowly day by day move the mats say 30cm closer to outside. Day by day they will get closer to the door, then you can slowly put them outside. Many dogs are more comfortable with this gradual change but i would recommend this as the last option
Good luck with her. be patient and i am sure your puppy will be a great dog.
Kind Regards
Todd Field