Green James1,
To read a register out of SDOUT:
1.Enable Reg Readout @ 0[1]
2.Write Dummy Data to your desired register, e.g. 21[XXXX]
3.Enable Reg Readout @ 0[0] for future writes.
See pg. 25 of datasheet and fig. 27.
Do you see the correct changes after your write command, for instance if you write 1[0], does the device power down and your current consumption drop?
I can't see any problem with your command set yet.
