Engine and C/H header tanks and overflow pipes

In front of the engine the coolant header tank has been mounted on the wall. Being led from the highest point on the engine it will hopefully be self venting.
To keep the installation tidy the overflow pipe has been routed from the back of the tank through the cupboard.
To the right the cream header tank for the central heating system can just be seen.
This will later be hidden by a door in front. The (just seen) overflow pipe from this tank is commoned up to the engine overflow pipe and exits the hull at the fitting just below the gunnel in bthe far corner.
The pipe also commoned up to this is the vent pipe from the calorifier (over) pressure release valve.
Because the calorifier will be mounted lower down (undert the bed behind the wall)  an inverted U has been included  so the engine or c/h do not vent into this leg.