A little late to this party but a good friend of mine just arrived in England this past weekend. She is a Fulbright Scholar and will be studying at the University of Kent, also looking at social work similar to the field in which are interested. Her two choices were the University of Kent's MPhil in intellectual and developmental disability or the University of Leeds' MA in DIsability, Health, and Illness. May be worth a look to see what their entrance requirements are. Having gone from a US BS in Anthropology to receive my UK MA, it can be done. You just need to find a program which works for you.