Add option to specify short units of centimetres and metres / inches and yards so separate them from national road network units

In the UK the road network uses miles and speed in miles per hour which are mandatory. However, many people use metric measurements for short distances like centimetres and metres in their daily lives so don't use inches and yards as these are not mandatory to know.

Unfortunately, both the sat nav and the proximity measurements will use yards and inches respectively in the UK when miles is selected to get distances and speed in the needed imperial mandatory units. This is unhelpful when the person wishes to use metric measurements.

In other words, if the person selects km then the sat nav and the proximity measurements will be metric as desired but the speed will be displayed in km/h which is inappropriate for the UK.