I'll have another look on Sunday. Thinking about it now, I'm sure I would recognise her if I was thinking about it. There's a cast appearence thread for appearences like this, but as it was the current episode, I'm sure it will be fine in here. Welcome to SB.
I think they have a really good stuff going with Stella and Ben, and also Jay, showing how teens can react if they don't have the attention from parents or family, as he doesn't from Bert. I really didn't want it to end tonight. I hated her, as well, Dave. With everything she's gone through with Katherine and her parents, and she's still willing to try to take away Ben's dad and destroy a photo of his Mum.