i am in the first year of a computer science course at imperial college london. i am really enjoying it, however there is a lot of maths involved. my course involves logic (natural deduction, propositional and predicate logic), maths methods (vectors, matricies, differentiation, series, sequences), discrete maths (sets and functions etc), programming (abstract data types, java, haskell, programming in general), hardware (how memory works, how the cpu works), reasoning about programs (checking for correctness of programs, proving programs work), graphics (the mathematics of graphics, and little bit of opengl), and databases (basically a little more than A-level computing!). [the bits in brackets are what i have mainly covered so far]
It is quite a hard course, im not sure what sheffield is like, but imperial work you hard!
there are good job prospects afterwards as you can go into many specialised fields. but you have to like computers and learning about how they work!
hope you enjoy it if you go for it
daven