"No, in the UK residential (and indeed all) lighting demand is going to continue to fall off a cliff thanks to LEDs and this is going to make a big impact on our electricity demand."
Between 2010 and 2012 the decline you note flattened out, and in three of four National Grid future scenarios lighting energy demand hovers around current levels for the next decade. And unfortunately DECC's other policies (like transport electrification, de-gassing heat), accompanied by a big expansion in house building will more than offset the benefits of more efficient lighting, leading to a near doubling of electricity use by 2050.
And in a world that uses much more electricity, DECC's ideas of building expensive, intermittent, low-load factor power sources like wind are pure idiocy. Almost as stupid as writing a blank cheque to EDF for Hinkley Point B.