Garage roller door motor not stopping when closed
I bought a new pair of straps and had another go...
Although I couldn't find any manufacturer's instructions for the door or motor, I did find some instructions for the remote control unit which mentions doors having screw limit switch adjusters. On my roller they look like the photo below.
With the door half open I decreased the travel for both up and down directions and slowly incremented them until the door stopped exactly at the top and exactly at the bottom.
I'm still scared to open and close my door without my finger hovering over the stop button, but so far it works and has saved me quite a bit of money.