Shelly EM Negative PF and Reactive Power - Highly inaccurate measurements?

Just installed a Shelly EM into my UK Consumer Unit. I have attached the 50A clamp around the incoming live tail.

Voltage, Power and Overall consumption are all positive, but PF and Reactive Power are negative.

The PF is consistently in the range of -0.67

The power measurement is way off, I am looking at consumption measured by my smart meter and it is showing 415w, but the Shelly EM is reporting 281w.

I have checked it is wired correctly, and even tried reversing the clamp. This turned the PF positive but the Power went negative.

N.B. There is no solar or any other load I am aware of that would negatively impact the PF.

Any ideas?

Thanks,

It is a single phase.

The CT is clamped around the main incoming tail, the em is wired into one of the circuits.