adowty sorry for the slow christmas-time response.
I decided to set up a quick example of communication from a NexusUI slider to Bela via websocket and OSC, it is here. Hopefully the README
should contain all the instructions, but feel free to ask if anything isn't clear.
To get the example onto your board, update to the dev-nexusUI
branch following these instructions (note this will delete your files from IDE/public
again).