KMH suddenly appearing on dashboard

[Gel]

Driving past a speed camera (known to me), I glanced at my speedo and was worried
as it showed 45!

Looking again I was relieved it was in kph, though distance travelled in miles.

Wish I'd taken a snapshot once parked; when parked, I went into SETTINGS,
mph was already chosen; pressed it again.

Dash was then back to normal.

[aljshep]

On some of the newer models, pressing the little knob (the one that used to control dashboard illumination) instantly switches between  mph and kph.  Could you have accidentally touched yours?

[Gel]

I'll check that; thought the stalk was just to adjust brightness.
Must admit I'm always a bit wary when cleaning dash, not to knock it.
Previous cars have had a roller switch to adjust brightness.

[Gel]

On some of the newer models, pressing the little knob
You're absolutely right on this; it just amends speedo dial, but ODOMETER remains
Imperial.
Sure that's not in manual.

[ceegee]

 The speedometer itself does not change as it is analogue but the display in the HUD changes from mph to kph, as stated this is does through the setting menu