There's lots of other grad schemes you can apply for:
https://www.brightnetwork.co.uk/graduate-career-advice/choosing-a-career/application-deadlines-graduate-schemes/That's the only list I can find right now but it's listed in order of application deadlines so that's quite useful. There's a few science ones on there, main one I know of is Wellcome Trust and I can see AstraZeneca on there too.
My advice is to also apply to some other generic grad schemes - some that you're not that interested in - just for the sake of practice.
Practice the psychometric tests and working on your written statements etc and even get some interview practice. It will build up your confidence and make you a stronger candidate when you apply for the grad scheme that you actually want. Even with a science degree, you can still apply to any grad scheme. They all lead to different routes like finance or IT but you'll find usually none of them specify a particular degree that they want you to have.
You might even end up liking some of the other grad schemes as you spend time learning about them and going through their application process. Good luck