Ok. so I am going to reply to my own post as I have had a bit of a break through. Here are my observations.
If the local temperature (i.e. TRV temp) is 20c, occupied heating setpoint is set to 30c with heating mode set to “heat”. I can then adjust the valve open degree and hear the valve changing. If the set point is below the local temperature changing the open degree has no effect.
If the local temperature (i.e. TRV temp) is 20c, occupied heating setpoint is set to 15c with heating mode set to “off”. I can then adjust the valve close degree and hear the valve changing. If the set point is above the local temperature changing the close degree has no effect.
It appears there is some interrelationship between the temperature set point, local temperature and the ability to change/adjust the open/close degree. I’m guessing this make sense is you are using the local/temperature and set point.
So, it appears if I want to have this fine control in my automations I will need to change the set point temperature on close/open to be above or below temperature as appropriate then i can adjust the close/open degree.
As mentioned above. Being able to exchange the local provided temperature for an external temperature (i.e. provided by a zigbee thermometer) would be great additional functionality.