Sadly for me, I was talking total rubbish in my last post (blame it on late night coding). I had a typo that meant the udm-dom.php was not loading. So of course, I had no "error", and because I only had a cut down menu, I didn't notice that udm-dom.php had not loaded.
Oh well, back to the drawing board, it does seem that there is a fundamental incompatibility between udm4 and protocol.
If anyone has any ideas on how to trouble shoot this, I'd appreciate them.