Right, after work, weather and moon got in the way I've finally got back to this.
I've tried a different camera and cable loom, and a new PC, and this was the result last night.
First, with the RA Gurley set to 'ignore'
And with the encoder enabled and set to 'TM'
All cables were dressed so as not to impede the movement of the mount, also the comm Loop was set to 100.
Not sure what else to try, anybody with any sugestions?