2013 CX-5 Sport Nav 2.2 Auto
I'm posting this on here in the hope that it may help others.
Back at the start of this year, we lost our rear reversing camera. We then had the city brake warning come on along with check remote key. I left the battery disconnected for 20 mins and everything reset. (Still no camera).
a few weeks later the fault returned along with no rear wiper and flashing AC lights. Another reset saw the lights go out but not the return of the wiper. Over the next months, we lost parking sensors, AC, rear tailgate opener, rear seat belt warnings and dimmable mirror. Add to this the return of the flashing dash warnings which now also included airbag, SCBS, Key, and the stop-start system.

I tried my local garage who could only tell me that the main CPU could not read the Rear BCM.
An hours drive to an auto electrical specialist added nothing as Mazda, after 4 attempts, failed to supply the correct wiring diagram for the car.

A second hand RBCM was fitted from a scrapper but this also failed to work.

So in the end I took it into a main Mazda dealer who, after a £120 diagnosis charge, found that the reason the camera failed was water ingress, tis allowed water to seep into the loom, slowly shutting down all the equipment as it sent the RBCM into shut down. A further £340 cost to replace the camera and loom section put everyting right again.

So if you live in a wet climate like us here in the UK, watch out for camera misting and get it sorted !!

Thank you to those on here who assisted with this over the last few months.