I run a childcare business - not a nursery, but same regulations. Maybe I can give some insight in to the hidden costs? Obviously these will vary but:
-Rent; in my area the number of buildings suitable for use as nurseries is pretty small so most are based in large converted townhouses. Properties that sell for £2-£3million.
-Rates; equally horrendous.
Staffing; on top of your straight ratio staff, most childcare providers will have others who are not included in the ratios as you need to be in ratio at all times. In most places the manager will be supernumerary, possibly add in a floater or two. You're also assuming that all of the staff are fully utilised (i.e. they always have 3 children, or 8 children) all of the time. IME this is rarely the case as there's a huge variation across the week in terms of numbers because lots of parents work part time. We try to recruit staff to only cover busy days but it's hard to find people so some days have a bit of a glut of staff.
-admin staff; you would not believe how much admin can be generated. Just the sheer volume of emails that need to be kept on top of, chasing payments, managing invoicing etc. People chop and change days, times etc which all needs responding to. Obviously admin staff are supernumerary
-toys and equipment. Good quality equipment is blooming expensive, but cheap stuff (designed for domestic use) tends to fall apart. We spend a fortune every single year replacing worn and damaged toys and equipment, plus upgrading and getting new things
-building maintenance. Again, really high. Even high quality commercial carpets get stained, worn, damaged etc. Walls get trashed, fixtures and fittings too. Might sound minor but it all really adds up very quickly.
-cleaning costs; most places pay cleaners (see above re mess and damage!)
-registration costs
-Staff training
-recruitment including PVG/disclosure checks
-agency staff
-sick pay
-pensions
-tax
-utilities (high, kids need warmth!)
-waste disposal (commercial and expensive, especially when you have nappies to dispose of)
It all adds up very very quickly.