You are right about each channel's it's own ID.
I tried these 2 one line urls for simplicity and swapping IDs does not work. It did some time ago.
BBC NEWS
vlc
http://live-997.ld5.edge.filmon.com/...4127f2c6cbfff7
BBC 4
vlc
http://live-889.ld5.edge.filmon.com/...97f0f29f25dc36