For old Landsat data, you can look in particular for the Global Land Survey collection, with the GLS 1975 epoch (with imagery actually acquired over a 1972 - 1981 period over Europe). Can be viewed directly from ArcGIS as an ESRI service, Cf. the blog entry.
I don't know of any Europe-wide Landsat-based urban cover for the 70s though. The noticeable exception being a 1975-1990 LCC analysis made for a research project, restricted on a 10km coastal hinterland, Cf. below