MPH to KPH

I have imported my 2014 phev rhd UK spec phev into france. finding the speedo kmh numbers are tiny and the french speed cameras are set very close to the limit i bought a OBD plug in digital HUD readout. Works fantastically well. very easy to read and keep within the speed limits.
The problem now arises that the speed limiter and cruise are both set in MPH. Is it possible to change this so they are actually set in KPH to avoid trying to do the quick maths conversion or trying to see what the speedo is reading?
TIA

On my occasional trips to the South of France I just use the Sat Nav GPS, which gives me Kph and adjust the cruise control to match (never used limiter). However, I also found I very quickly "learnt" the Mph equivalent, anyway. :idea: