I enjoy reading ERE and my spending is about £5,000 per year. However, this is artificially lowered by the fact that I live with my parents, and if I stopped being able to do that then to maintain the same spending I'd have to work hard to find a housing solution that was cheaper than "rent a place by yourself" and also possibly cut back on a couple of hobby spending categories I still have.
You're still relatively frugal living on the amount you said you live on - especially if you live in the south where house prices are more expensive. I'm pretty sure it would be very tricky for me to get more than about £1,000 lower per year than where I am without going full barebones or selling my car, which I need for work.
Advantages I have that allowed me to lower my spending this much:
I live in the north where everything in general is slightly cheaper.
I hate the taste of alcohol and also fizzy drinks so I only ever drink tap water and fruit tea. Maybe fruit juice once a month. This might be a big chunk of your grocery spending, depending on your drinking habits - I calculated once that my dad spends at least £1,000 per year just on alcohol.
I'm an introvert, so I don't feel the need to meet up with other people in places that require spending money more than once a month or so.
I don't fly for eco reasons so most of my holidays are either staycations or go-somewhere-cheapish-in-the-UK holidays. I did go on the Eurostar one time though, which was a little more expensive...
I take a maximum of two of said holidays per year. Normally my budget comes to under £200 for the whole holiday.
My family has a culture of cooking at home every night, and all of us can cook. We eat out about twice a year. The only other time I eat out is when I meet up with friends, and I'm not a picky eater so I usually go for the cheaper end of the menu, whatever it is.
A lot of my hobbies are mostly free, such as "read information on the internet", "self-study things on the internet", "read fanfiction on the internet", "go for a walk in the countryside that is on my doorstep", etc. I'm not strongly emotionally attached to any expensive hobby. I'm in one local club that requires a small weekly fee, but given I don't actually go every week I only spend around £100 per year on that, and I limit my book buying to around £240 per year tops and my cinema-watching to around £100 per year.
I think you get the idea. ;)
Some people might consider my life boring, but due to the nature of my personality, I find most of the things I do fascinating. If you have more extravagant tastes, naturally it will take more money to fund them.