Thanks Noel.
The main problem is the change from the 'slide' fixing on the Cougar to a 'twist' fitting on the later, more abundant mirrors.
I did think it might be possible to separate the ball and socket joints at one end or other of the Cougar stalk and mate that to a newer model with a similar stalk but I thought the re-assembly of the joint could prove problematic.
It would be possible to remove the windscreen side of the slide fitting from the Cougar and replace it with an OEM twist type fitting. A word of warning though; my mirror arrived with the windscreen slider in it along with a chunk of the still attached windscreen.
This would give you access to all the newer types and the covers for the stalk which also house the rain sensors, front view cameras etc but not necessarily the mirror wiring and connector. Having just recently helped my youngest to retro fit an auto-dimming mirror to his 2018 Fiesta we had to utilise the power feed to the interior lamps as the mirror wiring wasn't present.
I noticed 3 or 4 Mondeo Mk3 mirrors on eBay which would be suitable. Although the plugs are missing it would be easy enough to insulate a couple of suitable female connectors apart from each other and push them on to the relevant pins in the back of the mirror. You only require a power and earth unless you want to add the reverse gear interlock.
View attachment 18506
There are several OEM 'slide fit' mirrors complete with connectors on US eBay; examples:
Find many great new & used options and get the best deals for 05-07 Ford Five Hundred Rear View Rearview Mirror Auto Dimming OEM E11-015306 at the best online prices at eBay! Free delivery for many products!
www.ebay.co.uk
Find many great new & used options and get the best deals for 09-10 Ford F150 Auto Dim Rear View Mirror Tested #3426 at the best online prices at eBay! Free delivery for many products!
www.ebay.co.uk