Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Remove diverter valve microswitch cover

Observation:

With the DHW tap fully open the diverter valve spindle (with an actuator plate extending either side) moves down to its fully closed position.
This should have the following effect:
The actuator plate moves down and clear of L/H microswitch and at the same time depresses and makes the RH microswitch.