I'm not sure about this one from any angle but I'll tell you what I think I know about this subject, hopefully if I am mistaken at all somebody will keep me right.
bare with me here. I can't say how much of this applies to your Grand Scenic or what else you may have to consider, it's what I have learnt about espace III displays.
First off, i'd say it may be do-able but not necessarily viable:
The removal and refitting procedure may well be simple enough, it certainly is on my 2001 Grand Espace, a half hour job armed with the info and tools, hopefully someone has a specific procedure posted on here for your car
Then it gets complicated unfortunately.
You will need the keyfobs for the replacement dash so far as I can tell, I think it's to do with the RF rather than the transponder in the keyfob.
You will need a dash that has come from a car with the same engine and wheel size as yours, each engine has a code programmed in to the display by Renault that sets these parameters. Otherwise it will have to be set up by renault afterwards or the speed will not be accurate (wheel size) not quite sure what engine size has to do with it but it needs programmed nonetheless.
That is why it may not be a viable DIY job as it can be removed, sent for repair for about £150 and re-installed......by the time you get a display off donkeybay and get renault to set it up it's costing about the same. Further to this the repair company I checked out offered a warranty, I think it may have been as much as 3 years, Renault only offer a 1 year warranty for a brand new unit. Figures...
Then there's more...pfffff
The higher mileage will be memorised by the car. If the display you get puts your 40k car up to 110k it's not worth the bother as your car has depreciated far more than the cost of replacement with a brand new unit.
There may be more things I have missed but my best advice would be repair it yourself or get it repaired, it's the most economical option in the end.
If you can get a second hand display with two working keyfobs very cheap - that came off an identical car (ie; engine/wheel size/year?..) that has done a similair mileage then I don't see why it couldn't be done without any headaches, just remember that you will have to put the RF part of the new keyfobs into yours so that the key has the correct transponder in it to unlock the immobiliser.
There may be other background issues I'm unaware of or have missed, if anyone can add to what I have said or put me right if I've got it wrong here, please do so.
Best of luck to you mate, I have my display beside me as I type LOL, hopefully will find what I'm looking for