For middle income households like you, I think it depends a lot on your expectations.
Some people 'have' to change their car every three years so always have car payments.
Some people 'have' to have endless beauty treatments, cut and colour, high end make up and creams etc that costs tens, if not hundred plus a month.
Some people would never take a packed lunch to school, work or on days out so spend hundreds of pounds a month on food and drink out of the house.
Some people 'have' to have the latest mobile phone so in a family spend £100+ a month on mobile phone bills.
Some people buy their household goods from John Lewis or high end independents, which is usually far more expensive than Ikea, supermarkets etc.
Some people think normal basic shopping is organic everything from Waitrose, so the £800 you've allowed wouldn't even cover that, let alone fuel and entertainment on top.
If you're in any of the above categories, it might be tight. If you're a more frugal spender, it's probably fine.
Definitely look at your normal, pre covid spending patterns for costs for general spending, eating out, days out etc.
Maybe try and live on the new budget for 3 months and see how it feels? If anything, you'll build up some savings to put towards moving costs etc
Also, if you haven't done so already, have a really good review of your budget, to make sure you've covered everything and got everything at the best price. It's often possible to save a decent sum if you've never changed utilities, broadband, TV package etc.
www.moneysavingexpert.com/banking/budget-planning/
On the matter of the £562, it's probably a good ballpark for annual and irregular expenses, especially if that figure includes a holiday. Many people say their finances have been derailed by an 'unexpected' car repair, vets bill, broken appliance, or because it was Christmas. But in reality, they've failed to plan for normal expenditure that will happen sooner or later so needs to be included in their spending and saving decisions.