For those who don't understand why the issue OP is facing is a real problem for all of us, rather than some kind of just deserts for being successful, this article is a good read:
“Like many of my colleagues I have young children and claim funded childcare hours,” says the thirtysomething family doctor. However, the doctor points to the “tax cliff edge at £100,000”, where if a household earns this much or above it loses this funding.
“This is coupled with the loss of the personal allowance from earnings over £100,000, which results in a marginal tax rate of 62% including national insurance. Factor in pension contributions and student loan repayments, and I would only take home 15.5p for every pound earned.
“I did some calculations and realised that, factoring in the loss of childcare hours and the higher tax band, I would need to earn about £120,000 to ‘break even’ with earning just below £100,000.
“As a result, after Christmas I’m reducing my hours to keep my earnings down. This means at the busiest time of the year for the NHS I’ll be sitting at home twiddling my thumbs when I could be at work seeing patients.”
Reducing hours to stay below the £100,000 income threshold was, they added, “a regular topic of discussion” among colleagues. “It’s utter madness. Apologies to patients who can’t get in to see me in February and March. I’ll be back in April.”
https://www.theguardian.com/politics/2023/nov/21/im-reducing-my-hours-fiscal-drags-impact-in-the-cost-of-living-crisis