Radiographer here
Bad news is that they will definitely have elements of AS level Chemistry, Biology and Physics (depending on University). Perhaps check every uni to see who has the least.
Good news is that I only had one module in first year and I found it to be easier than A-levels due to the multiple choice nature of the exam. After 1st semester there was no more pure science; it then became about how to use radiation in clinical practice. The further you progress in the profession, the less you will need to understand how electrons interact with human tissue. You just need to understand how to operate the machines and acquire images. Many radiographers will not like that I said that haha but I stand by it.
I graduated 3 years ago and would struggle with A-level sciences now. Therefore, it does not form an integral part of the profession afterwards unless you choose to go into academia I guess.
Final note: radiography will be a horrible waste of your time if you are not passionate about it. Not only does it sound like you are going to have to push yourself academically, but the salary will not compensate for a lack of passion. I currently work in industry and am earning more than most in the NHS. However, I am still working alongside idiots (that don't even have a formal qualification to their name) on the same salary. If you are doing it for the glory then remember that the general public will perceive you as a nurse.