Earlier quoted context omitted.
I am British! I haven't used imperial for at least 15 years apart from for speed limits, which I ignore anyway.
Except you subconsciously have. All display sizes are sold in inches. The trip computer on your car will tell you miles per gallon. Even if you ignore speed limits, your speedometer gives you your speed in MPH :). If you've ever flown on a plane, altitude has been given as feet and distance in miles. So you do use both.
If you fly a plane (not just on a plane), those are nautical miles, not land miles. And speed in knots. And rate of climb in ft/min.