I'm doing physics A2 at the moment and am loving it.
Having said that it is very hard, and without a firm grasp of the mathematics involved it will be hard to fully appreciate the beauty of some of the topics involved (eg, in gravitational fields if you use partial differentiation on gravitational potential you find you get gravitational field strength).
The topics are very interesting though. I'm not sure about OCR but with AQA we have an optional module, which can either be Turning Points, Medical, Applied or Astro. Nuclear stuff is compulsory.