Thanks so much. Really appreciate your assistance and guidance on this.
Would I be able to drill though this and be able to fix shelves/TVs to it without a problem?
Yep you will, without any problems.
It may be an idea to have a quick chat with a structural engineer so that you can put your mind at rest and to help you choose what you're looking for though. Everyone on a forum can tell you their opinion but an engineer can give you the full storey in relation to and specifically to your 'design'