I think "well off" here is relative. Higher rate tax payers are not some sort of fat super rich. The majority of us have progressed through "ordinary" jobs and are on PAYE, so no accountants etc like the genuinely high earners.
If you're a middle ranking civil servant, teacher, serviceman etc, you are likely going to be caught by the higher tax bracket (which hasn't really changed substantially since I started work in 91…
I've paid the higher rate of tax since 2003 and have become progressively worse off during that period.
Childcare costs are incredibly high, especially if you are living / working away from family support networks (Normo Tebbs told my generation to "get on our bikes" – so C2W is an ironic benefit!!!). Friends of ours were paying nearly £800 / month for 3 days nursery care for their daughter…
… and it doesn't stop when they go to school. School hours and holidays are notoriously incompatible with workplace hours, so we need morning and evening childcare for ours – or one of us stops working…