anyway, dont choose derby, it's too far away from the univ campus.
after u arrive at liverpool, u could go to the accommodation office regularly. because some postgraduate students will move out from MG in Sep. it possibly means some rooms in MG will be free to rent at that time.
mg is not available to 1st yr undergraduate students.
mc seems 2 be the best choice for you.
if internet connection is not that important to you, u could choose anges jones. the furnitures there are not bad and u could access internet by using dial-up services.