I agree that it totally depends how you think and also it's a 'how long is a piece of string' question as to whether the amount is reasonable.
As the OP has already clarified that she's sorted her pension and saves for large purchases, so this is genuinely spare money, it's fine. If she was having to borrow to get her car through its MOT or other irregular but essential expenditure, less so and obviously she should cut down her 'fripperies' budget so she had a better emergency fund.
As to whether or not it's 'enough' as well as deciding on the amount based on how much spare money you have, it also depends on what sort of wants you have, some people could piss through it in far less than a month, others wouldn't make a dent in it.
As it happens DP and I have about this amount of 'pocket money' and have operated this system for over a decade. He is a spender, constantly looking for the next thing he can buy. My wants are far more modest and I often get to the end of the month and find that I've bought a couple of bottles of craft gin, 3 kindle books at 99 p each and been out to lunch a couple of times (I rarely buy clothes and spend absolutely nothing on personal grooming, I don't even have hair cuts because my hair breaks before it grows) and have spent about £80, whereas DP has spent £5/600 on bike stuff. So I buy premium bonds with the money I haven't spent. I have over £40k, and that's all because of the differences in our spending over time, he consistently spends about £2/300 a month more than I do.
Some people see a pot of money and think 'what can I spend it on' but not everyone thinks like that, so it depends a lot on how you think about money as to whether a general pot of money for free spending on non essentials is helpful or not, which I think it is, because then you just spend what you like without worrying that you don't have enough for essentials or aren't saving enough, if there's money in the pot, you can spend it, if there isn't, you can't.
How you think about money probably affects how you see those 'save the change' apps that skim off bits of money into a separate account whereas a lot of people rave about them, saying things like 'I saved £120 in a month without even noticing' as if it magics money out of thin air, whereas if you're a saver and less interested in spending, you just see it as 'well if it wasn't doing that, the money would just sit in my current account instead'.