So I've followed the datasheets instructions:
Here's the sch:
I've built two boards.
With just the component on, R6 (R24 on mine) measures 300k W/O the 200k resistor soldered on. So that's an internal impedance.
Obviously when I solder R24 and R23, the 300k Rinteral and 200k R24 measure to 120k.
Vts stays at 50%ish Vin, so the charger never turns on.
I've set this PMIC up in an isolated manner (no other components attached). That also means no current on Vout, which I'll test now to see if it affects anything.
Advice appreciated.