Can stream ONLY local content to DLNA TV problem

Hi all, spent the best part of 2 days trying to sort this out before giving up and coming on here.

Running Linux Mint 17.3 – all up to date.
Running Kodi Jarvis 16.1
Using a “WDTV Live” DLNA box connected via HDMI to my TV.

I can send my music, pictures and local video to my DLNA box (“WDTV Live” box), connected to the TV just fine.

However, if I select a Video add on, such as BBC iPlayer, or Youtube, and select “Play using” (in my case the “WDTV Live” box), nothing happens, nothing at all. I get no indications of anything on both my Kodi screen and on my TV.

Note, the iPlayer and YouTube works fine on the local PC.

I even installed Kodi 16.1 on my laptop and took it to a friends house where he has a DLNA Sony TV, but the same problem exists.

Am I doing something wrong?