It massively depends what you are counting as 'bills'
In my head there are the 'core' bills which have to be paid, no matter what:
Mortgage
Council tax
Water
Elec and Gas
Car insurance
Home insurance /life insurance
After these core bills we have several thousand left but there is still a lot has to come out of that.
The there's a whole lot of other bills which actually if we were completely completely skint and in real trouble we could cut:
TV /Internet package
Kids private tuition costs (not private school fees, stuff like maths tutor if struggling with gcse)
Kids extracurricular costs like sport/drama/music clubs
Memberships of professional bodies
Other subscriptions for phones, small subscription type apps
Union membership costs
This sort of stuff takes out probably another £600 - £700 per month
Then you have stuff like food, petrol, clothing, transport costs, which while not technically bills? Have to be paid, they are essentials, and they are pretty big sums for most people. If you really include everything, like food, car fuel, haircuts, dentist, optician, clothing, money for birthday and Christmas gifts, school trip costs, even modest amounts for little bits of socialising.... This is going to be easily £1500 for most families, half of it alone will likely be food/petrol. You also can't avoid home maintenance costs which might be irregular but do have to be paid eg boiler servicing, the washing machine breaks and you need a new one etc etc.
So while it would be easy to say there's thousands left after bills that would be naive, the reality is a lot less than that after real essentials are paid, and that's before luxuries like holidays, some will have luxury lease car costs.