It's got recessed shelves on the kitchen side. That's my "larder".
I don't want to get rid of thee original Victorian door or architrave in case a future owner wants to reinstate the door. I have no basement, no garage, nowhere to store the door.
I don't want shelves in the living room because a new TV is going to be attached to the wall on a bracket right in front of this unused door, and seeing the architrave, frame, door and panels showing around the new TV is very distracting to the eye. So I thought, panel it over, and paint it the same colour as the wall, and it will "disappear".
Have had the hardboard cut to size now, so shall be using it.
Thanks for the replies. Still don't know whether to use caulk or sealant. Nearly 4pm and still haven't started the job.