OK, I have no idea what changed (I don't see any new changes on gerrit apart from possibly this:
http://gerrit.rockbox.org/r/#/c/2083/) or if this was always working and I've been losing my mind - but I decided to take another look and this is working for me now 100% !
I'm using build 38cceb9 and I can play, pause and skip forwards and backwards with the remote.
This freaking awesome!!
Many thanks to everyone who has put time in to developing rockbox, I _really_ appreciate it!