PS4 – How to Uninstall the BBC Player App on PS4

There is no way to do it (at least for now). You are required to be online to view trophies. Quote:

The PlayStation 4 will not allow users to look at their Trophies or Friends lists when the console is offline, Polygon has learned using a retail unit received for review purposes.

The PS4 still doesn't sync Trophies in the background — every time you load up your list of virtual accomplishments, the console takes a moment to sync with Sony's servers. Perhaps because of that, you can't view your Trophies list if you're not connected to the internet. On PS3, you can scroll through your Trophies whenever you want, and you can sync them the next time you're online. You can definitely earn Trophies while playing PS4 games offline, but if you try to look at your list when you've disabled the console's internet connection, you'll get the following error message: "[Connect to the Internet] is turned off. (NW-31484-0)"

As the PS TV works over Wifi, no port-forwarding is required to connect to the PS4. What you need to do is possibly connect the PS TV using ethernet to improve the connection. If you cannot connect the PS TV to Ethernet, try using a Wifi booster to increase the signal.

You can also try enabling "Direct Connection" for Remote Play on the PS4 and see if that makes a difference to your connection. The only port forwarding you may need to do is on the PS4, for certain online games.