@ajb2k3 Ok thanks.
FYI and anyone else that would like to get the ENV III data on CoreS3, I managed to get it working using I2C directly.
Here is the code to go in your loop assuming I2C has been initialised as the default i2c0 variable:
i2c0.writeto(68, '\x2C\x06', True)
data = i2c0.readfrom(68, 6, True)
temp = (((data << 8 | data) * 175) / 0xFFFF) - 45
hum = (((data << 8 | data) * 100.0) / 0xFFFF)
I then output this Temperature (C) and Humidity (%) formatted using (assuming you've initialised label fields already):