Having scanned the Octiy to clear the Airbag warning light (After removing the battery for installing the amp and other radio bits) I thought I'd scan the rest of the car whilst I had the cable. Could anyone shed some light on some of these errors?

I'm guessing the overboost error is sticky VNT's in the turbo but not 100% sure as the limp mode comes and goes.

17055 - Cylinder 1 Glow Plug Circuit (Q10)

P0671 - 000 - Electrical Fault

Freeze Frame:

RPM: 0 /min

Torque: 232.0 Nm

Speed: 0.0 km/h

Load: 0.0 %

Voltage: 11.78 V

Bin. Bits: 11000100

Temperature: -1.8°C

Bin. Bits: 00110000

17057 - Cylinder 3 Glow Plug Circuit (Q12)

P0673 - 000 - Electrical Fault

Freeze Frame:

RPM: 0 /min

Torque: 232.0 Nm

Speed: 0.0 km/h

Load: 0.0 %

Voltage: 11.78 V

Bin. Bits: 11000100

Temperature: -1.8°C

Bin. Bits: 00110000

17058 - Cylinder 4 Glow Plug Circuit (Q13)

P0674 - 000 - Electrical Fault

Freeze Frame:

RPM: 0 /min

Torque: 232.0 Nm

Speed: 0.0 km/h

Load: 0.0 %

Voltage: 11.78 V

Bin. Bits: 11000100

Temperature: -1.8°C

Bin. Bits: 00110000

16618 - Boost Pressure Regulation

P0234 - 000 - Limit Exceeded (Overboost Condition) - Intermittent

Freeze Frame:

RPM: 3276 /min

Torque: 326.0 Nm

Speed: 111.0 km/h

Load: 78.8 %

Voltage: 14.29 V

Bin. Bits: 11000000

Absolute Pres.: 2233.8 mbar

Absolute Pres.: 2590.8 mbar

16502 - Engine Coolant Temp. Sensor (G62)

P0118 - 000 - Signal too High - Intermittent

Freeze Frame:

RPM: 1764 /min

Torque: 136.0 Nm

Speed: 77.0 km/h

Load: 29.4 %

Voltage: 14.59 V

Bin. Bits: 11000000

Temperature: 41.4°C

Temperature: 40.5°C

Cheers