All,
I had previously used a similar guide to below to get RADIUS with Groups support working:
https://openvpn.net/vpn-server-resources/integrating-active-directory-with-access-server-using-radius-and-post_auth/
The previous one had an AD.py instead of the python attached, however as of 2.75 (and as far forward as 2.8.2) this is no longer working
I have updated the script and it is now working, an updated version can be found on my github:
https://github.com/garysteers/openvpn-as-scripts/blob/master/post_auth_radius_mapping.py
Hopw this helps a few people out...