Had a very strange reply from Mazda via a conversation on their Facebook page. Text as below - note the section in bold text...
Me - Trying to find out the safe water wading depth for the CX5. It's not in the manual, the dealer doesn't know (and, frankly, doesn't care) and I can't find it on-line anywhere. 5 March at 12:42
Mazda UK - Hi Alan, the CX-5 doesn't come with a recommended wading depth as it is not intended for off-road use. If you have any other questions, please don’t hesitate to ask us. Thanks
7 March at 08:37
Me - Who said anything about off-road use? I'm talking about it's ability to deal with flooded roads, which is obviously something of an issue currently. And, I'm surprised that Mazda would say that it's not intended for off-road use as that rather defeats one of the objectives of a 4x4 SUV? Certainly, most of the main auto publications have been quite complimentary about it's off-road abilities, so they clearly think is is designed for it?
7 March at 09:54
Mazda UK - Hi Alan please can you send us a private message with your vehicle reg and contact details? Once we receive this we will ask your Customer Relations Manager to discuss this with you in more detail. Many thanks
7 March at 15:23
Me - Sent as requested.
7 March at 19:40
Needless to say, despite a message saying I'd be contacted, I've heard nothing yet.