I say go with Royal Holloway. Go where your interests lead you. Contrary to popular belief, the world will not automatically open up for you if you have a degree from a prestigious school. Also, 3 years after you're done with the program, where you've gone to school will not matter. Not an objective answer, but a subjective one based on personal experience. Then again, i have a social sciences degree. That'll be 9 dollars. Please drive up.
The cosmos is also within us. We're made of star stuff. We are a way for the cosmos to know itself - Carl Sagan