Please advise on avoiding 60% tax trap vs work pension contribution via Salary Sacrifice

CityLatina

Going around the circles between my HR/Payroll, HRMC and Youtube so here for your rescue please! Thanks in advance.

I am trying to figure out how I can avoid getting trapped by the 60% tax over £100k. My basic salary is £111,200, employee benefit allowance of £7k, annual bonus of £20k (paid 20th April 2023 during 2023/2024 tax year) then again £30k 28th March 2024 (same tax year). I contribute £695 monthly via employer salary sacrifice scheme (net!) to the work DC pension while they contribute about £1621monthly. I have two children under 16s (13y and 15y) for child benefit consideration. I am the breadwinner of the house, no other income.

As such I was thinking to follow the below tax strategy; wondering if it would make sense to you experts:

• Pay the full March 2024 bonus onto the DC work pension
• Given that I cashed out my bonus last April (stupid me!), my annual gross taxable figure in Feb 2024 payslip is £122,644 which when March 2024 pay is made, this figure will bring my annual gross taxable figure to £131,910. Needless to say if I do not do anything I am scheduled to have my tax code changed to 0T which means 'zero tax free allowance'. If I increase my monthly pension contribution from March 2024 to March 2025 to £2090 (£23k per year) then in May 2024 submit an adjusted net income for tax year 2024-2025 makes sense? All I want to do is to reduce my taxable income down to £100k. Or because I was stupid to cash out my bonus last year I will have to ride out the upcoming tax year 2024-2025 with no personal tax allowance then to reset it in April 2025?
• Regardless I have no idea how I could avoid paying 60% on above £100k annually if my basic salary is £111k and my pension contributions are net paid? Does it mean that every year I will get trapped? Can I not contribute the excess of £100k onto my work pension to remove this tax trap?