Depends where you are in Oxon and how you drive, but assuming you are in Oxford, I would go M40, A43, M1,A50 (to Uttoxetter) and follow the signs on the local roads. Thats about 120 miles. If you drive at 70 the whole way, you should do it in 2 hours.
Very true. I should have said '70 up to Uttoxeter' as that is all dual c'way/m'way. Its only about 10 mins from Uttoxeter past Rocester to Alton...unless it is the dreaded school holidays!!!