Having solved my problem via another topic thought I would share solution.
During cold weather i.e. 5c or under the Auxillary Heater ( 1.6 TDI SEL ) automatically kicks in and as a result causes idle rpm to increase to constant 1000rpm preventing battery drain. Solution is turn this off via the heating menu - press munu on fan speed control knob - select options on bottom right of screen - deselect auto auxillary heater. Idle rpm will now remain steady at 750 irrespective of other options selected. E.g. Heater, A/C heated seats etc.
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