I'm not too happy about the position of the extruder on the print head.  The motor rubs against the X axis belt when mounted in one direction, and the large cog rubs the belt clamp in the other.

Also, the two bearings that hold the hobbled bolt, in the extruder, are not perfectly parallel, and this causes the bolt to be slightly stiff when turning.  We shall see if this causes problems and needs to be revisited.