Ummm… Well I tested the sensor on my Enviro pHAT with the voltage divider and saw the readings coming back between 0 and 3V, so wired up my voltage divider to my Pi Zero and Explorer pHAT but still got the same result… Interestingly I have a LED wired up to GPIO16 on this Pi Zero and just before it locks up whilst reading the analog input from the Explorer pHAT; the LED flashes momentarily…
I think I might swap the Explorer pHAT out for the Enviro pHAT to get this project moving on… Next time I think I will use an ADC chip like the MCP3008…