I can only speak to my experience.
I was on on £28k when I started mat leave, went back when DD was 9 months old, paying £900 a month childcare fees which was tough financially.
By being at work I was able to progress, seek promotion and development.
I got 1 year of government childcare funding when DD was 3 years old, which reduced my monthly childcare costs to £240 so the government paid about £3000 towards her childcare in that year
DD is now 5 and I earn £50k which I expect to go up to £65k in March next year.
Since returning to work after Mat leave I have paid the government in excess of £20k in tax and NI.
Had I chosen to be a SAHP, my DH is earning £18K, so minimum I would get according to 'Entitled to' is £300 a month, which assuming I claimed for 4 years until DD started school would be about £14K the government would have given me and I would have a 4 yr gap in employment so would be less likely to return at even the salary I left at.
So in my experience returning to work and being supported with childcare was a better deal for me and for the government accountant.