No, i can have the TV on, but as as soon as i plug the Aerial cable into either the freeview box or the tv, the NM drops by 6-7. (which desyncs the router)

Ive got another tv from my sister, and the NM hasn't dropped. It seems the TV was somehow causing large interference when it had access to the aerial signal. (it didn't matter if i moved the tv to a different location)

problem resolved, the tv i got from my sister has been on for around 30 minutes now with no unstable NM or drop in NM