In Surrey, combined income £80K ish, 2 children at independent secondary schools (no bursary), and money is tight. We do manage to "save" £500 a month, but it's budgeting rather than true saving as we have to dig into it for car repairs/replacement washing machine/school trips/holidays etc, so the "savings" get depleted almost as fast as they build up.
We can only do it because we paid off the mortgage, so our living expenses are low, and have built up a good cushion of savings, which allows us to cut our finances so fine.
We have just over £1k to spend each month after all essential bills and savings are paid, to cover food (about £300), petrol (about £150) , clothes, entertainment, extra curriculars, general expenses etc. That's just about enough money, but not enough to be extravagant. Holidays are simple, meals out are rare and bargains always looked for!