Current batteries are not viable for use as storage for the national grid to provide supply to cover fluctuations in supply from wind power. You'd need many GWh of storage replaced far too often.
Organic flow batteries might be able to do the job, if they existed as more than lab prototypes.
except they are. tesla has been selected to build an 80mwh battery bank to smooth out los angeles power supply. They plan to have 1.3Gwh by 2020 of storage.
modern batteries do not die in short period, or lose their storage potential quickly.
people also aren't taking into account the cost of nuclear waste.
every which way you look at the nuclear plan, it is full of money pits and issues.
Please do some calculations before putting your hopes in batteries as a viable form of grid storage to support the utopia of majority renewables.
Current winter peak demand is 60GW before the Climate Madness Act requiring 80% CO2 reductions by 2050 means all heting and cooking needs to be CO2 free as well.
60GW times 4 hours a standard SFA block for grid management purposes therefore requires 240GWh and equivalent battery storage to provide that even at £100/kWh is £24Bn. In practice in the winter if you were at some notional 100% renewables you might need at least 72 hours supply not 4 so maybe £432Bn on storage. Push the cost of the actual generation assets. How long do batteries last 10 years? That might be £40Bn a year to maintain your battery capacity.
I honestly don't expect the solution to be as above but the costs are provided for illustration.
Drive to your nearest stil operating coal station, the big black mound beside it is probably enough to keep it running full load for 3-6 months.

please do some proper maths.
we are not saying create all our power from renewables over night. why you have gone with 60gw is bizarre.
Hinkley C is just 3GW, if your going to compare costs, do it like for like.
and the cost of thousands of years of nuclear waste storage, which people like to ignore?
let alone the cost to build, then decommission. the 10 year time scale, which is likely to slip?
what we do in that 10 year build widow, as we need more now.
Similarly, I'm really interested in the potential for electric vehicles to act as mobile batteries.
Anyone with an EV has a 20-50 ish kWh store parked outside. With smart meters and some clever electronics the car could charge when grid demand is low and discharge into the house to run appliances etc. when supply is low.
and is something national grid is already looking into, and you would be paid if you let them use your batteries. national average is less than 25 miles per day driven, leaving most people more than able to generate some income by allowing battery bank to be used in grid.