Regarding the 15 free hours of child care -DD2 only does 2 days at nursery (10 hours per day) so we only qualify for 13 hours free. Our nursery calculates your entitlement and spreads that across the year so your bills don't change each month, but then reconciles it at the end of your nursery life to see if you have over or under claimed.
I'm lucky, when I had DS we paid gorgeous a full time nursery place, costing around £1,000 per month, that was 8 years ago.
After having DD1, we had a nanny for a year costing about £1,400 per month for a 3 day week. My mum covered one day and DH who works shifts insisted on the same day off mid week each week (family business).
When DS started school DD1 went to the nursery, but they could only give me 2 days, so mum picked up the slack.
After DD2 was born I took a very short leave as we simply could not cover our outgoings on my SMP. I am the main wage earner.
I have just received DD2's first invoice with her EYFE and perhaps now I can start to make inroads into the debt mountain that has accumulated over the last 8 years.
I once estimated my child care costs, and gave up once I reached £80,000 as it was too depressing for words. This only covered nursery fees, nanny wages and tax, after school club and holiday club.
We have done what we can to minimise costs. DH now has 2 regular days off so I cut out one day of after school club for the older two. In the holidays we ask for him to either have Friday off, or to start at 6 so I leave a little early rather than pay a day of child care.
MIL helps out if kids are sick, or I can work from home.