The heat valve on its adapter pipe fits to the outlet 'A' at the back of the inlet manifold, with a hose to the lower port on the heater matrix. The upper port on the matrix is connected to pipe 'B' that is clipped to the underside of the inlet manifold and runs to the front:

'A' is the hot coolant outlet from the inlet manifold to the lower port on the heater matrix. 'B' is the return from the upper port on the matrix to the pipe running under the inlet manifold:

At the front of the engine the heater return pipe under the inlet manifold comes out at 'A'. 'B1' is the port on the front of the inlet manifold that is a pipe travelling through the inlet manifold to near the back where it is open, which goes to 'B2' on the back of the front cover. 'D' is the top hose to the radiator:

'A' is a short hose from the heater return pipe under the inlet manifold which tees into the large bottom hose port on the pump. 'B' is another short hose from the front of the manifold to a port on the back of the front cover. 'C' is the pump inlet from the bottom hose, and 'D' is the top hose from the thermostat housing to the radiator:

The port on the back of the front cover comes through towards the pump at the arrow, and the slot bounded by the ellipse:

The pump body is flat where the port comes through the front cover at the arrow, so coolant flows along the slot in the front cover (the ellipse) to a hole which goes through into the large port for the bottom hose:

The steam-pipe between the inlet manifold and thermostat cover: