Hi Brian
Many thanks for the update. I am now getting all three readings correctly.
View, Extra Sensor Real Time Graph now shows:
Extra temp 1 9.0C
Extra hum 1 50%
Extra temp 2 7.1C
Extra hum 2 57%
Extra temp 3 7.1C
Extra hum 3 58%
They all agree with the WMR89 main console.
Many thanks for your help.