Just noticed this on my maxidot does anybody know why this would happen?

What do you mean exactely? Multi Function Display = Multi Function Indicator = Maxidot = FIS = Driver Information System, they are all synonymous....

Sorry should have been clearer, when I bought the superb 4 weeks ago the maxidot screen in the middle of the display displayed MFD however it now shows MFI is this something I should be concerned about ?

Did you bring the car back to the garage for any servicing/updating since you got it? As far as I know MFD is the usual name for the car trip computer in the menu. I haven't seen MFI anywhere. One very annoying possibility could be that there's a bad connection to the screen and the round part of the 'D' no longer displays leaving the straight 'I'. You can check this by going through the menu looking for missing pixels in this location when other options are chosen.