Where was GTA2 based again? Was that Liberty, or London?
No, London was used for the two expansions; 1969 and the lesser known 1961.
GTA2 takes places in an unknown city (referred to as Anywhere City) in the near future, assumed to be in 2013. However, it's split into the same generic districts as Liberty (Industrial, Commercial and Residential), so it's possible, but it's not meant to be any city in particular.