the O levels or equivalent is a must.
Science can be combined science, not necessary pure science as stated in the website.. It had been advertised in the papers before as a "science" subject and not specifically a "pure science".
it is correct to say they do not look into your results once you are called for interview.... else they wouldn't call u at all right?
quite a few guys without degrees got in too. but i would reckon the ratio to be 20% non grads to 80% grads.