Why's that? My girlfriend's MX5 import is in kph and she's never failed an MOT for it.

 

Check this:

http://www.motester.co.uk/forums/forum3/82.html

 

If it's like any other 164, it's pretty easy. You need to get a very small flat-bladed screwdriver (or similar) with a bent end and very carefully prise out the two small panels either side of the base - under the row of minor gauges but just above the panel light dimmer roller (on one side) and above the warning light test push button on the other. BE CAREFUL and pull them out a little bit each side because they're on two long plastic locating pins and if you just lever one end out, one of the pins snaps. This will expose a couple of pan head screws. After that, the rest should be come self-explanatory. 15 minutes should have it out.

 

Thank you very much for all your advice ! I think that we'll try and get it through the MoT on the kph speedo. don't want to be changing it again in 3 or 4 months when we go to France!