Hmmm...nice! Maybe not quite in keeping with the rest of the CX-5’s styling!
After replying to Gwynno's original post, I spend a few minutes doing a bit of armchair-based web research in to temp gauges using the car's diagnostic port and it seems there are several possibilities. You can get additional units that plug into OBD2 port to show all kinds of data (including water temp) some of which are head up display versions that project onto the windscreen. Another method is to use an OBD2 wireless or Bluetooth adapter with smart phone app (of which there are several for IOS and Android and which is the approach that interests me the most). All of these would be completely portable to other cars (assuming they use the same OBD2 standard) which is an extra benefit.
I haven't used any of these so cannot endorse any but if you want to know a bit more about what's going on with your car/engine, it appears there are ways you you can do so for a relatively little outlay. (The wireless/Bluetooth adapters start at about £20 depending on the the type and some of the apps are free).
Just a couple of points to note: It appears that not all of the adapters work with IOS so if you're an Apple/ iPhone user, you may need to check carefully that you're buying the right one. Android phones seem to be more straightforward. Secondly, I read that the OBD2 port is powered constantly, even with the ignition off and the car locked so something plugged in that's drawing power could drain the battery over time and may therefore need to be removed when not in use. The OBD2 port on the CX-5 is just beneath the lower kick panel, below and to the left of the bonnet release.