Hi LeeB2
This is the setup I am using with my Drayton Wiser. You don't need the sel and stat switches they just allow me to access the boiler modes if the wiser unit is off.
https://docs.google.com/document/d/1WOzBxuSfKQd794h3AR6HfgqHePmpg3eigSaO3riqxZI/edit?usp=drivesdk
grnunn