Nah don't need all that hassle - just press the RH buttons to scroll through the 'exercise' 'connect' 'test' 'setting' menu screens to 'settings'. Select settings, then scroll through settings to get to the 'general' screen, select and scroll through to get 'units' which toggles between metric and imperial. 10 second job.
BTW you can download the user manual from the
Polar website cheers for that i had the polar webpage but i still couldnt work it out it was a 10 second job after all cheers.