"We don't go there at night" Damn. that's a Sign!
My shop is 30 miles away,, a 25x40 steel building in the middle of a rundown residential trailer park.
Hey, it was a bargain!
I'd had it about 2 years, long enough to fill it up with tools. I drove up one evening to find the door swinging on the hinges.
Everything of value was cleaned out. I had never insured it, but I check with my homeonwers carrier anyway. I was delighted to find I was covered under "off-premises" coverage.
It was 10% of my homeowners coverage.
So, I added up my losses and got a nice check, went shopping for new tools

Mind you, this was a automotive stuff, when I was racing but not yet machining.
I did add a HD deadbolt, and I bought a 2-zone wired alarm box from Radio Shack. I have motion sensors and door switches on it, a loud siren out of reach, and a strobe.And warning stickers.
That's been about 10 years and so far no one appears to have tested it.
Today it's full of machine tools, so I really need to look into adding coverage.
I also carry a pocket pistol all the time, and have a revolver hidden in the shop.
You Brits need to fix that legal problem you have.