The USB on my router is evidently to connect a modem, does not support storage
Anyway, I found an ethernet switch in my cupboard and that works well between Hummy and LG. I can now see the files on Hummy's internal drive from the LG and stream them over the ethernet connection. They play with glorious surround sound!!
That's a good enough fix for what I want to do, although I still cannot see why the Hummy cannot play the edited surround sound
I am not however able to see the files on the USB HDD, plugged into the Hummy, from the LG. Yes, I do have custom firmware on my Hummy, but my knowledge of Networking is VERY basic! If I were able to reconfigure as SMB or NFS, as you suggest, would that enable me to see the USB hdd as well? That would be nice.