Thanks for the suggestions. I have considered astrochemistry before, but for me, the current pathway is get up to graduate level ability in physics & maths - a tough nut to crack but I am working on it - whether I learn formally or not, the thing that I feel will get me through the door to astrophysics is not necessarily an honours degree in physics, but simply being able to prove that I have an adequate founding in physics and math - a lot of work lies ahead!