It is possible to remove the inner board and stash it in the headliner. The board can be accessed by using hard plastic like a trim remover to prise off the glass surround and the connector is a tight fit to get through the hole in the stem but it does fit with a shove. Wrap the board so it is insulated (poly bag maybe), route the connector in the headliner out the edge at top of windscreen and connect then slide the lot into the headliner space. https://www.youtube.com/watch?v=PS9ewyBsnzU
This will give you an idea how to do it and his alternative method of removing the switch panel to get the board hidden.