There are big issues for discussion in KS45, including the way in which scientists tell stories to account for the universe(s). These stories find common ground with world religions as science is about "probability" and "possibility", like history or RE, rather than "certainty" and "proof".
Where might God be located in all this? In another dimension? In all the universes? As a non-corporeal Force (back to sci-fi space ships again!)? What religious questions might time travel answer? Will solving these "deepest secrets of the universe" just open up more and deeper questions? Those pupils who are fans of rationalism will want to know whether God could be just one of these "thingies from another dimension stirring the water". But the relationship between rationalism, credulity and imagination would be a good one for Year 13 high-fliers.