Just a quick update and request for info.
Lucas Mesu has been extremely helpful with this problem. An initial skype with Lucas identified a broken motor drive shaft. I sent the motor back to Lucas and received it back all fixed and ready to reassemble. Reassembly was accomplshed with another Skype call today and once you know what to do, reassembly is pretty straitghforward. I wouldn't recommend trying to remove and reassemble a drive motor without information from Lucas. There are some key marks on the gear and torque is fairly critical. Having seen the inside a bit, I can confirm that these mounts are really high quality precision engineering. Mine has been great until the dec motor shaft problem, but support and service to fix it was first rate.
So onto the information request to Don, I am thinking to reduce the acceleration as I've got a big (ish) scope mounted - it's a celestron C14. So I guess I'll need to visit servoconfig to make a change. Any thoughts on what to change and by how much would be great. I guess the same applies to deceleration too.