Right, okay I'm a little confused, but I've got past that issue.

I am using modrana on the device, which is python based, but "$ which python" gave no results (I assume modrana uses a library?).

So I installed python using pkcon and now when I paste in a url I no longer get that error. If I try a BBC iPlayer link I get to the play symbol, but pressing that results in the error "No URI set". I assume this is something to do with youtube-dl, but it works with mpv on my linux box (last time it didn't I was on an old version of youtube-dl).

It's not a huge issue for me, I'm not likely to want to watch much on the phone. I'm just looking towards when the tablet comes out.