Yes I used the same form factor half minicard AC7260.HMW in both PC's.
The laptop was originally fitted with an oem N6235 card. The desktop was made up from parts by myself and originally used a standard TP-Link Dual Band PCIe adapter, but to be able to use WIDI, I changed to a BPlus MP2H-7260 PCIe adapter into which is fitted an AC7260.
Since my OP I have not had seen another AP Crash reported but it might be too soon to tell. I don't really understand what the Zero Configuration Service is all about but to give it some chance, I have now set the Proset / Wireless Zero Configuration Service to Automatic (Delayed Start) in Services.
Edit later: Just as well I reset the Proset / Wireless Zero Configuration Service to Automatic (Delayed Start) from Disabled because the Intel WIDI wouldn't connect.
For the desktop system we recommend instead the Intel® Dual Band Wireless-AC 7260 + Bluetooth for Desktop since this adapter is already designed for desktop systems.
The integration of wireless adapters for laptops is subject to compatibility and wireless regulatory approvals.
In the case of the laptop we suggest contacting the system manufacturer for a list of validated adapters. Furthermore, if the laptop came preinstalled with the Intel® Centrino Advanced-N 6235, you already had an Intel® WiDi compatible wireless adapter.
I apologize for any inconvenience this may cause.
Thanks. I was half expecting a stock answer that I have seen provided for others that doesn't give a proper answer in response to the on going problem which I have probably solved anyway.
I thought about installing the Intel desktop version but decided to get the alternative which although in my opinion does exactly the same job, it has a better antenna and certainly does not have the USB connection lead for Bluetooth power wiring fault.
As regards the regulatory business, I see that newer versions of my laptop now come fitted with AC adapters and retro fitting an AC adapter is a much cheaper option. I am fully aware that I already had WIDI. In common with both PC's, there is a marked improvement in 5 GHz and inter PC file transfer speed and there are no other problems.