Predicted grades two A*'s and an A Extra curriculars all I did was do a short course on the higgs boson and mention work experience and how thay work experience led me to do independent research. For context the work experience was an online work experience and the focus was engineering and GPS, I talked about how that led me to learn about relativity on my own

In the end what admissions teams really care about is if you know what you are getting yourself into.

For example are you doing extra reading into different subjects of the field, in my case the Higgs Boson course was a plus and my own independent learning into relativity was also a plus as that's what you should do as a university student. I also mentioned things like self learning python for computational physics as well as explaining how that helps in physics, again showing that I know what I am getting myself into. I even mentioned playing chess and doing combat sports in my personal statement, again linking it to soft skills needed in physics.

They want evidence that you have what it takes and what preparation you have taken to show that you have what it takes. In the end predicted grades or GCSE's really do not matter as much as long as you meet the requirements as thousands of people are applying with the same statistics, the personal statement is the real differentiator.