3 hours is loads. Even if you have to collect luggage and re-check it.

I think you misinterpreted the reference to a "coach tour" which was just meant as a humourous reference to the fact that you most likely will have to be bussed from the plane to the terminal, which of course adds a few minutes to the arrivals process (and given that you had incorrectly told us your transit times, every second counted in your initial scenario).

Bottom line - don't worry.