Just as I did with the cockpit floor I sealed the edge of the seats to the hull with wood and later carefully epoxy filleted them.
At the rear of the cockpit is a storage locker for smelly items (stove fuel, cheap camping stove and gas bottle, paint etc) that you don't want to allow the fumes from into the cabin. It will drain into the cockpit and then out through the transom. Below shows me constructing it from three pieces of ply, with doubler on top for an access hatch.
And from underneath with wood to screw the hatch into:
Below after the epoxy set. The hatch is just sitting there and the front is yet to be trimmed. It was also not glued to the supporting beams so I could remove it for further work in the cockpit until closer to transom fitting.
After removing the smelly locker lid I dry fit the transom laminated beam (further most one) and the quarter deck front beam.
I marked out notches for a 90mm x 20mm hardwood king plank, and epoxied it all in place. The other wood each side of the king plank is just to hold the beams in place until the epoxy set.
Below is the final result, this will have two layers of 6mm ply on top once the transom is in place to complete the deck. Love the curves!