As for point one they are much less reliable because they are intermittent. I'm skeptical of how much cheaper renewables are. I haven't noticed energy prices declining recently. Correct me if i'm misinformed. I'm slightly confused by point 2. What are you saying, because soviet technology is getting sunk a lot we should stop bothering with having a navy?
Either way you are giving way to much credit to the power of the UK military industrial complex.
The UK is aiming for around 27GW of battery storage by 2030.
But it's not a simple picture. The grid needs to be expanded to distribute power from renewables more efficiently, batteries aren't the only storage option, and the concept is still too centralised.
A combination of distributed rooftop solar with domestic batteries, maybe local storage in substations, strategic national storage, and a mix of sources would be a more effective strategy than trying to park huge batteries around the country in the hope they'll be big enough.
The UK still has a post-war mindset around energy which doesn't make sense in the 21st century.
So build three times as much? Solar has gotten cheap enough that such solutions are quite viable these days. And as a bonus, electricity will be basically free during the summer.
take a look at all the roofs next winter, if its anything like the other side of the canal, you'll see that the average roof coverage is substantially less than 1/3.
Either way you are giving way to much credit to the power of the UK military industrial complex.