PGCE in physics or maths or both?

I'm about to enter my final year of undergraduate physics, planning on training to teach secondary (and potentially sixth form too?). Some unis, including UoM where I currently study, offer a Physics & Maths PGCE. Some, like Oxbridge, only offer them as separate courses. I'm really stuck on which to apply for when applications open! Could I train in physics, then teach maths later, or vice versa? Or could the combined course almost double my prospects?

Then again, I'm not sure which subject would suit me more. I feel confident that I could handle the material of either physics or maths, but Im wondering how the challenges of teaching physics or maths compare. Which is more fulfilling? Are physics practicals/labs a total pain?

Would it be reasonable or desirable to teach both physics and maths? Would a physics teacher be expected to also teach some chemistry and biology? Is there a discernable difference in pay, and promotion prospects, in either department? As a female teacher, would I be in demand or disadvantaged at all?

Apologies for the long list of questions. Any answers at all, or suggestions of factors I've not considered here, would be much appreciated.