You do realise that Oxford and Cambridge will be more interested in a level results than gcses? And those mock results are very, very good - If she improves on those, as I'm sure she will, that will be fine.
I really, really hope you did not use the word "appalling" in front of your dd. She must be very intelligent and hard working to even get those grades, she doesn't need bashing.
You really need to take a step back and let your dd lead the way. There is absolutely no good pushing your dd to revise and achieve top grades if her heart isn't in it. Not everyone that can be academic wants to be. Be careful or you could really damage your relationship with her.
I was the top kid in school. At one of my parents evenings my head of year told my mum I had the potential to be one of the top women in the country. I went on to win a scholarship (fully paid) to a top school to do my a levels (from a normal state school).
I applied to Oxford. My mum was so excited, I would have been the only one from my family who went to university. I was accepted into oxford, ucl, Kings college and so on.
And you know what.... I was desperately unhappy. I hated the pressure of it all. I hated all of it. So after a lot of soul searching I turned all of of the offers down and went to work,full time. I feel even now my mum is deeply disappointed for me rather than loving me for who I am.
I still had a good career- I ended up a senior marketing manager earning a very high wage, working alongside the kind of people I would have graduated with.
However, I still wasn't happy. I just don't enjoy being around people and work. So with the support of my dh I am now a sahm! We manage on dhs wage, which is minimum wage and we have two dc. I have never, ever been happier. Honestly. I have no pressure. No stress.
Don't pressure your dd. It's her life. Let her make her own decisions. Academia isn't everything.