I am an electronics and comms engineering with Masters in space systems and am currently working in spacecraft development for the LISA spacecraft in the Uk (am 26 now.) I am a physics enthusiast as of now and am seriously thinking to pursue academic career in Physics (GR and Cosmology in particular). I started from slightly above (from Hamiltonian mechanics) the basics. I am only reading textbooks, practising couple of problems and listening to lectures. I am also afraid because I have been quite successful in my career. I would ideally like to enrol to casm (Part III) to a couple of years, by when I hope (wish) to kid of go through pre-requisite subjects for Part III General Relativity. I have mailed couple of universities about my eligibility for a PhD, but they thought I have less knowledge of Maths, to deal with GR/Cosmo as of now and the professor from Oxford suggested doing experimental Physics PhD. Ok... enough of background: basically I am fix. I am interested in theoretical Physics more. I dont exactly know what is experimental physics. Will they get a chance to know theoretical physics? I have two questions: 1. Based on what you know about the people admitted CASM, is it likely for me to secure a place after another two years of self study - by then I will be 28! 2. Or Is it better, to do experimental physics focussing on gravitaional waves, CMB etc I would greatly appreciate you valuable suggestions/advices. Thanks.