I have finally been able to add support for Fritz and Chessbase, but only the 64 bit versions: Fritz 15 and above and Chessbase 13 and above. And because they load the driver from the Windows\System32 folder installation is a bit messier.

So those GUIs now support the following boards:

Certabo (USB and BT)
Chessnut (USB and BLE)
DGT (USB and BT)
DGT Pegasus (BLE)
Millennium ChessLink (USB, BT and BLE)
Novag Citrine (USB-Serial)
Novag UCB (USB-Serial)
Square Off Pro (BLE)

More information at https://goneill.co.nz/chess.php

Graham