It finally completed after many crashes. For some reason Eagle is not very good at auto routing large boards. When it gets to the optimisation stages it ends up crashing with no stack trace or bug report. Not very helpful to report back to Eagle.
It actually came back with 100% completed but Exxos and I need to go over it as it has probably ripped up some tracks that were already placed. I can already see some areas that could do with taking out and routing manually to improve.
Not so easy to see the routes, but here is a pic without the GND planes etc turn on.