Your bookstore options are:
1. Purchase a used book. Students sometime sell their books between semesters. Availability is limited and not guaranteed.
2. Purchase online via the school's website. Prices are reasonable compared to U.K. prices and students can purchase used books too.
http://www.stchris.edu/bookstore.htm
3. Univ of Luton bookstore. Most books are available but things are expensive now in the U.K. The current exchange rate is approximatley 1.9:1. If money is not a problem, this a good choice for those of you who need a book in an emergency.
http://finance.yahoo.com/currency
4. Other U.K. bookstores in London and Cambridge. See the school's website for addresses.
http://www.stchris.edu/bookstore.htm
They are listed at the bottom of the page.