45 minutes?!
No comment, I just can't think of anything to say! Surely they need to spend a week at least looking at each individual seat that they sell and fitting each one separately? You can't generalise fitting instructions by Group, I guess basically you can but each seat will be fitted slightly differently.
I know how to fit my own car seats and could do it with my eyes closed, but if I was giving a lift to a friend and she was bringing her own seat I would not be confident of fitting it properly if it was not a Britax seat (that's all I've ever had!). I would get my friend to fit her own seat.