I have a 2008 Bighorn 3400RE with a 40" Olevia on the back wall. To get to the controls I have to remove the left panel (see the photo). My panels are made of a foam board. It is not wood so be careful with it or be ready to replace it. My dealer removed the left panel and mounted a set of stab latches, like those used on cabinet doors. One at the top and one at the bottom. The right hand panel is held on my small nails.
How to remove the TV, I don't know, but there are a few 2x4's in the back and probably has a TV mount attached to the 2x4's. Wish Heartland had provided a way to remove the TV or at least tell us how it is mounted so we can work on it or replace it.
Fortunately our Olivea has been working very well. It seems that the smaller Olivea TV's mounted on brackets have failed.
Let us know where your 40" TV is located and what the cabinet around it looks like. Maybe we can give you more information.
BC