Re: natual consumption reduction
...that's a good point - I wonder if the DfBEIS factored the cost of batteries in their energy (un)savings?
Probably not. A more substantial battery problem is that the gas smart meters are mostly (if not universally) powered by a sealed battery with a life expectancy of ten years (also generally the certification life). As a sealed unit this means that the gas meters will need to be swapped out every ten years, and recalibrated, or thrown away and replaced.
In theory the old style "classic" meters certification rules give a ten to twenty year removal and recertiifcation timescale, although in practice those can be left in use for 25 years or more and still work fine, whereas the smart meter simply stops working when the battery is dead.