Well, disconnecting the battery made no difference, seat back off, connector off, quick spray of cleaner and reassemble, and jobs a goodun.
I give up, ill just do this every now and again....
FYI
Measure, Original data, after disconnect, after connector reseat
System Voltage      13.59 V      13.98 V      13.79 V
System Voltage Status      Okay      Okay      Okay
Airbag Configuration      Side Airbags      Side Airbags      Side Airbags
Pretensioner Configuration      Driver&Passenger      Driver&Passenger      Driver&Passenger
Driver Airbag Squib Circuit Resistance      3.13 Ohm      3.03 Ohm      3.05 Ohm
Passenger Airbag Squib Circuit Resistance      2.17 Ohm      2.12 Ohm      2.10 Ohm
Driver Pretensioner Circuit Resistance      2.59 Ohm      2.61 Ohm      2.56 Ohm
Passenger Pretensioner Circuit Resistance      2.43 Ohm      2.41 Ohm      2.41 Ohm
Driver Side Airbag Squib Circuit Resistance      5.15 Ohm      5.15 Ohm      3.42 Ohm
Driver SAS Message Status (Side Airbag Sensor)      Okay      Okay      Okay
Passenger Side Airbag Squib Circuit Resistance      2.46 Ohm      2.43 Ohm      2.43 Ohm
Passenger SAS Message Status (Side Airbag Sensor)      Okay      Okay      Okay
Reset Passenger Side Airbag After Activation (DTC69)      Inactive      Inactive      Inactive
Reset Driver Side Airbag After Activation (DTC68)      Inactive      Inactive      Inactive
Reset Pretensioning Devices After Activation (DTC67)      Inactive      Inactive      Inactive
Driver SAS Initialisation Status (Side Airbag Sensor)      Okay      Okay      Okay
Driver SAS Communication Error (Side Airbag Sensor)      None      None      None
Passenger SAS Initialisation Status (Side Airbag Sensor)      Okay      Okay      Okay
Passenger SAS Communication Error (Side Airbag Sensor)      None      None      None
DTC set since      21000      21000      21000