The monthly costs for my baby in her Amsterdam daycare are 1700 Euros for a full-time place. The hourly cost is above that which is refunded by tax, as most Amsterdam daycares are. We get 1/3 of 1500 refunded by tax, so we pay about 1200 net for the baby. My husband and I are both academics and our income is too high for us to get more than 1/3 for the first child. In SE UK our full-time place will be about 800 pounds per month, using vouchers, so it will indeed be cheaper. Note that the waiting lists for baby places in Amsterdam are years long - people put themselves in waiting lists when 13 weeks pregnant and often don't get a place until the child is two. That's why the daycares get away with being so expensive for their quality.
For our older daughter we have out of school wraparound care, which costs 900 Euros per month. We get back about 500 Euros per month in tax for her care but with the coming reforms it is likely that we would get less back. We will end up paying about the same on average in the UK for her care, but we haven't been too happy with the out of school care in NL and we're hoping that the after school clubs in the UK will work better.
I have to say that for us it has been very demoralizing to pay 1600 Euros per month for daycare in a country where we are already paying over fifty percent tax on much of our salary. We are academics, not bankers. We are not rich. Our net salaries in the UK will be quite a bit higher, and daycare won't take up as big a fraction of my net income.
@ the poster who mentioned PISA testing. Yes, NL performs better than the UK. But this is only one measure. For an above average child I have no doubt that the UK system is better and offers more to them. But again this is subjective, other families may be happier with the NL education system. (Mind you, at least half a dozen expat families we know have left NL in the last year mostly because of dissatisfaction about the schools.)