Bro it's a fence. You're not a cow, a physical perimeter shouldn't be an insurmountable obstacle. Just climb it. Do recommend wearing a coat you don't care about though, I've ripped a couple of them climbing fences.
Look at the picture you posted, it even has ridges sticking out that you could use to try and plant your feet on. I'd also recommend gloves but that's just cus I love gloves. Walk into any Toolstation and ask for cut-proof gloves. They're like 7 quid.
You can't really know about security unless you scope the place out but that can be a bit bait if you're being bait about it. I'd just go for it and be careful, if security are there then just jump back over the fence or, more sensibly, walk the perimeter prior to entering and look for things on the other side of the fence that you can jump on to make a quicker escape. There's always something. If you do get caught then just don't be aggressive, and leave if they tell you to leave.