Firstly the right hand carriage side was removed from the carriage.
I turned a disk with a small hole to locate one arm of the dividers at the centre of the trunnion, and positioned the quadrant gear. Then super glued it, and its pinion, into position. Marked the locations. The super glue will be removed later.
The bevel gear case was located through the pinion gear hole, and keeping the control handle shaft level. The case was drilled and bolted into position. The control handle shaft will be replaced by one of smaller diameter, in keeping with the 1:10 scale.
A couple of days in the workshop working out how to position those parts and drilling, tapping, and reaming. The other cannon will take less time.