I found a contradiction in the plans. One of my next actions was to cut out the plywood to make up the transom. According to the plans the transom is made up of 2 layers or laminations of plywood with an Iroko capping at the top all faced by an Iroko layer to the exterior. The thickness of the plywood I was expecting to cut is 12mm. According to the cutting list, the thickness of the capping piece is 30mm. As you can see in the picture of the plan below, the thickness of the 2 laminations of plywood and the capping piece should match. Issue!
I do have on my cutting list, sheets of 9mm ply, so the question is whether there should be 3 laminations, 2 of 9mm and 1 of 12mm or is the thickness of the transom capping given incorrectly in the cutting list.
The solution was to send the question to David (recent builder of a Golant Gaffer), who confirmed that the transom capping should be 24mm thick. Good to have someone to check with!