Re: import/export meters and storage
Do the current specs for the smart meters incorporate export metering?
Yes. SMETS2 compliant smart meters are required to record active export of power.
However, that's not really material for most people, because the main payments (for older PV contracts) are the generation component (recorded on your PV generation meter), and the export element (a further and much smaller payment) is at present usually guessed at 50% of the generated power. Export metering for domestic users will for the most part merely shift the incidence of those export payments between different PV households to those who don't use as much of their PV output from those who use more. If you can it is generally better to use on site and not to export because the additional export rate is usually much lower than your grid imports.
Having said that, the whole UK PV scheme has been a misbegotten scam, throwing money at a technology that doesn't help us at all, and puts up evertybody else's bills.