Thanks so much for your help.
I edited the setting for the advanced camera (Camera 3) to enable click drag. The setting for the simple camera (Camera 4) is set to true by default. I wanted the click drag capabilities of Camera 4 combined with the tilt and rotate objects functionality of Camera 3. In essence, a hybrid camera. I hope that makes sense!
Before receiving your reply, I managed to get the game working by enabling vsync after starting a new game via the Options.ini file AND by playing in offline mode.
OK, I tried the suggestion of setting up a new account on my Mac and playing with that account. Same thing happened. Immediately after creating the mandatory sim at the beginning of a new game and exiting CAS, the game got stuck on the loading screen, this is despite enabling the vsync option.
I was considering purchasing some expansion packs, but I really feel like I need to get to the bottom of this before I start investing cash in the game!