Polar CS 400 display

mm1

For reasons that I cannot fathom my Polar CS 400 has defaulted to show heart rate and altitude and I cannot figure out how to get it to show HR and current speed, which is all I am intetested in for training and TTing. I have tried resetting and going through the start up menu from scratch, but to no avail. Any thoughts on how to fix this problem, which is driving me nuts, would be very much appreciated.